KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
CHEMISTRY THEORY (043)
SAMPLE PAPER NO- 1
BLUE-PRINT
CHEMISTRY (043)
Class: XII
S.No Chapters
MCQ
1
Mark
1
SOLUTIONS
2
ELECTRO CHEMISTRY
2(2)
3
CHEMICAL KINETICS
3(3)
4
d BLOCK Elements
2(2)
Coordination
A/R
1
Mark
VSA
SA
2
3
Marks Marks
3(1)
Case
study
question
4 marks
LAQ
Total
Marks
5
MARKS
70
7
4(1)
2(1)
5(1)
4(2)
7
5(1)
2(2)
2(1)
9
3(1)
7
7
5
compounds
HALO ALKANES
1(1)
2(1)
3
6
AND HALO ARENES
ALCOHOLS,
2(2)
6(2)
8
7
PHENOLS & ETHER
CARBONYLS &
8
3(1)
5(1)
8
CARBOXYLIC ACIDS
9
AMINES
10
BIOMOLECULES
3(3)
1(1)
3(1)
3(1)
6
4(1)
8
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII
CHEMISTRY THEORY (043)
Max. Marks:70
Time: 3:00 hours
SAMPLE PAPER NO-1
Read the following instructions carefully:
a) There are 33 questions in this question paper with internal choice.
b) SECTION A consists of 16 multiple-choice questions carrying 1 mark each.
c) SECTION B consists of 5 very short answer questions carrying 2 marks each.
d) SECTION C consists of 7 short answer questions carrying 3 marks each.
e) SECTION D consists of 2 case- based questions carrying 4 marks each.
f) SECTION E consists of 3 long answer questions carrying 5 marks each.
g) All questions are compulsory.
h) Use of log table and calculator is not allowed.
SECTION A
This section contains 16 multiple-choice questions with only one correct answer. Each question of the section
carries 1 mark. There is no internal choice in this section.
1. What products are obtained when aqueous NaCl solution is electrolyzed?
(a)
Na at cathode, Cl2 at anode
H2 at cathode, Cl2 at anode
(b)
(c)
H2 at cathode, O2 at anode
Na at cathode, O2 at anode
(d)
1
2. The following cell is found to have the standard cell potential of 2.36 V. What will be standard
reduction potential value of magnesium electrode?
1
(b)
−1.36 V
(d) −2.36 V
(a)
0V
(c) 2.36 V
3. The molecularity of an elementary reaction cannot have which of the following values according to the
collision theory?
(a)
2.5
(b)
1
(c)
(d)
3
2
1
4. The rate law for the reaction, A + B → Products is: Rate = k [A] [B]2. The rate of this reaction at 298 K
is found to be 0.25 mol L−1 s−1. What is the rate constant of the reaction if [A] = 1 mol L−1 and [B] = 0.2
mol L−1?
1
2
−2 −1
2
−2 −1
(a)
6.25 L mol s
(b) 0.16 L mol s
(c)
100 L2 mol−2 s−1
(d)
16 L2 mol−2 s−1
5. To what order of a reaction does the following graph belong to?
(a)
(c)
Zero order reaction
Second order reaction
(b)
(d)
1
First order reaction
Third order reaction
6. How does the increase in the pH affect the K2Cr2O7 solution?
1
(a)
It cause the K2Cr2O7 solution to release CrO3 gas
(b)
It causes the coagulation of K2Cr2O7 solution
(c)
It causes the K2Cr2O7 solution to change its color from orange to yellow
(d)
It doesn‟t bring about any change in the K2Cr2O7 solution
7. Which of the following elements can stabilize the higher oxidation states like +6, +7 and +8 of
transition metals to the greatest extent?
(a)
Nitrogen
(c)
Chlorine
1
(b)
Fluorine
(d)
Oxygen
8. How many moles of AgCl will be obtained when CoCl3.4NH3 is treated with excess
AgNO3 solution?
(a)
1
(c)
3
1
(b)
(d)
2
0
9. Identify the wrong statement for the coordination compound [CoCl2(en)2]+.
(a)
The cis isomer of the complex is optically active
1
(b)
The coordination number of cobalt in the complex is 6
(c)
The oxidation state of cobalt in the complex is +1
(d)
The complex has an octahedral shape
10. Name the main product obtained when an alkyl halide is reacted with silver cyanide. 1
(a)
Alkyl cyanide
(b)
Alkyl isocyanide
(c)
Aliphatic amide
(d)
Carboxylic acid
11. For the best yield of ether from Williamson’s synthesis, the alkyl halide should
preferable be:
(a)
Primary
(c)
1
Tertiary
(b)
Secondary
(d)
Acidified
12. The esterification of alcohols involves the breaking of which bond in alcohols?
(a)
Carbon-oxygen
(b)
Oxygen-hydrogen
(c)
Carbon-hydrogen
(d)
Carbon-carbon
1
For Questions 13 to 16, two statements are given – one labelled Assertion (A) and the other
labelled Reason (R). Select the correct answers to these questions from (i), (ii), (iii), and (iv) as
given below:
1×4=4
(i)
Both Assertion (A) and Reason (R) are correct statements, and the Reason
(R) is the correct explanation of the Assertion (A).
(ii)
Both Assertion (A) and Reason (R) are correct statements, but the Reason
(R) is not the correct explanation of the Assertion (A).
(iii)
Assertion (A) is correct, but Reason (R) is an incorrect statement.
(iv)
Assertion (A) is incorrect, but Reason (R) is a correct statement.
13. Assertion (A)
:
During the nitration of aniline, 47% of the product formed is
meta-substituted.
Reason (R)
:
During the nitration of aniline, anilinium ion is formed that has the
meta-directing —NH+ group.
14. Assertion (A)
:
Reason (R)
:
Benzene diazonium chloride reacts with phenol in alkaline
medium to form a coloured dye.
Benzene diazonium chloride is resonance stabilized.
:
Primary amines cannot form intermolecular hydrogen bonds.
15. Assertion (A)
Reason (R)
16. Assertion (A)
Reason (R)
:
In primary amines, the nitrogen atom is directly bonded to two
hydrogen atoms.
:
Human beings are incapable of digesting cellulose.
:
Cellulose is a polymer of fructose.
SECTION B
This section contains 7 very-short-answer questions with internal choice in two questions. Each
question of the section carries 2 marks.
17. State Kohlrausch’s law of independent migration of ions and give its mathematical expression.
2
OR
The graph shows the variation of molar conductivities of two electrolytes, A and B with
concentration. Identify the weak electrolyte and explain what accounts for its increase in molar
conductivity as the concentration of its solution approaches zero.
2
18. What are pseudo first order reactions? Give an example.
2
19. A first order reaction takes 69.3 minutes for 50% completion. How much time will it take for
80% completion? (log 2 = 0.3010, log 5 = 0.6990, log 8 = 0.9030)
20. What type of structural isomerism is exhibited by the following compounds?
2
1+1=2
(a) [Cr(NH3)5Cl]SO4
(b)[Cr(NH3)6][Co(CN)6]
21. What do you mean by:
(a) Racemic mixture
1+1=2
(b) Chiral carbon
OR
Answer in brief:
1+1=2
(a) How does branching in carbon chain affect the boiling point of isomeric alkyl halides?
(b) In dihalobenzenes, the para-isomer has higher melting point than ortho- and
meta-isomers. Why?
SECTION C
This section contains 5 short-answer questions with internal choice in two questions. Each question of
the section carries 3 marks.
22. How many grams of ascorbic acid (vitamin C, C6H8O6) must be dissolved in 75 g of acetic acid
to lower its melting point by 1.5ºC. The Kf for acetic acid is 3.9 K kg mol−1 and the atomic masses
are C = 12 u, H = 1 u, O = 16 u.
3
23. Write the IUPAC name of [Ni(CN)4]2− complex and explain why the complex is (Any two): 3
(a) Square planer in shape
(b) Diamagnetic in nature
(c) Homoleptic.
24. How will you convert:
1×3=3
(a) Bromobenzene to toluene
(b) Propene to propan-1-ol
(c) Chlorobenzene to phenol
25. Write the reaction mechanism of acid-catalysed dehydration of ethanol to form ethene. What
product is formed when ethanol is heated with conc. H2SO4 at 413 K?
26. Write the chemical equations for the following reactions:
3
1×3=3
(a) Gabriel phthalimide synthesis
(b) Hoffmann bromamide degradation
(c) Isocyanide test
OR
Answer the following questions:
1×3=3
(a) The pKb values of CH3NH2, C6H5NH2, and C6H5CH2NH2 are 3.38, 9.38, and 4.70
respectively. Arrange these amines in the increasing order of their basic strength.
(b) Write the IUPAC name of the compound:
(c) How would you explain aniline‟s inability to give Friedel-Craft reactions?
27 Give a chemical test to differentiate between:
3
(a)Benzoic acid and benzophenone
(b) Formaldehyde and benzaldehyde
(c ) Ethanol and phenol
28 . (i) What do you mean by denaturation of proteins? Give an example.
(ii) What are essential amino acids ?
SECTION D
This section contains 2 case-based questions with internal choice in one of the sub-questions that follow
the passages. Each question of the section carries 4 marks.
29. The four colligative properties of the dilute solutions help in calculating the molecular mass of the
solute which is often called observed molecular mass. It may be same as the theoretical molecular mass
(calculated from the molecular formula) if the solute behaves normally in solution. In case, it undergoes
association or dissociation, the observed molar mass gives different results. The nature of the solute in
solution is expressed in terms of van’t Hoff factor (i) which may be 1 (if the solute behaves normally),
less than 1 (if the solute associates) and more than 1 (if the solute dissociates). The extent of association
or dissociation is represented by : (n=no of particles after dissociation/before association)
Based on the above passage, answer the following questions:
(i) What is common in all the four colligative properties?
1
(ii) What is the expected value of van’t Hoff factor for K 4 [Fe4 (CN)6 ] when it completely dissociates
in water?
1
(iii) What is the value of van’t Hoff factor for dilute solution of K2SO4 in water by considering complete
dissociation?
2
OR
What will be the van’t Hoff factor if the solute
A+B-is
40% dissociated?
30. The communication between different cells in our body is established by certain chemicals called
hormones, which act as chemical messengers. Hormones are a group of biomolecules which are produced
in the endocrine or ductless glands and are carried to different parts of the body by the blood stream
where they control various metabolic processes or show physiological activity. They are required only
in very small amounts. Like fats and carbohydrates, they are not stored in the body but continuously
being produced.
In mammals, the secretion of hormones is controlled by the pituitary gland located at the
base of the brain. A general classification of hormones is given below.
a. What do you mean by endocrine gland?
1
b. What is the similarity between fat and hormons?
1
c. Why hormones are considered chemical messengers?
1
OR
Which gland controls the secretion of hormones in humans?
1
d. By reading the above passage, differentiate between steroids and non-steroids
hormone.
1
SECTION E
This section contains 3 long-answer questions with internal choice in two of them. Each question of
the section carries 5 marks.
31. Answer any five from the following cell:
3+2=5
Sn | Sn2+ (0.02 M) || Ag+ (0.1 M) | Ag
Given: E° Sn2+ / Sn
= −0.136 V and E° Ag+ /Ag = 0.799 V
a) Write cell reaction.
b) Between Sn and Ag which one is more reducing?
c) Calculate E°cell.
d) Write one use of salt bridge.
e) Predict whether the reaction is spontaneous or not?
f) Can we store Ag in tin container? Give reason for your answer.
g) Calculate Ecell for the above.
32. Give reasons:
1×5=5
2+
a) The compounds of Zn are colorless.
b) Among the first transition series, chromium is the hardest metal.
c) Scandium does not show variable oxidation states.
c) Transition elements form interstitial compounds.
d) Zinc, cadmium, and mercury are not considered as transitions elements.
OR
Answer the following questions:
3+1+1=5
(a) What is lanthanide contraction? Mention its cause and any two consequences.
(b) Cerium, in its +4-oxidation state, is oxidizing in nature. Why?
(c) Write the balanced ionic equation for the oxidation of iodide in the presence of
alkaline potassium permanganate.
33. Write the structures of A, B, C, D and E in the following reactions:(CBQ)
5
OR
Write the main product of the following reactions:
Differentiate chemically between the following pairs of compounds?
d) Ethanal and Acetone
e) Pentan-2-one and Pentan-3-one
3+2=5
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII
GROUP -4 (James Chadwick) QP 1
Time allowed: 3 hours
Maximum Marks: 70
MARKING SCHEME
Questi
on
No.
Value Points
Mark
s
SECTION A
1.
(b) H2 at cathode, Cl2 at anode
1
2.
(d) −2.36 V
1
3.
(a) 2.5
1
4.
(a) 6.25 L2mol−2s−1
1
5.
(b) First order reaction
1
(c) It causes the K2Cr2O7 solution to change its color from orange to
1
6.
yellow
7.
(d) Oxygen
1
8.
(a) 1
1
9.
(c) The oxidation state of cobalt in the complex is +1
1
10.
(b) Alkyl isocyanide
1
11.
(a) Primary
1
12.
(b) Oxygen-hydrogen
1
(i) Both Assertion (A) and Reason (R) are correct statements, and
the Reason (R) is the correct explanation of the Assertion (A).
(ii) Both Assertion (A) and Reason (R) are correct statements, but
the Reason (R) is not the correct explanation of the Assertion (A).
(iv) Assertion (A) is incorrect, but Reason (R) is a correct
statement.
(iii) Assertion (A) is correct, but Reason (R) is an incorrect
statement.
SECTION B
● At infinite dilution, when dissociation of electrolyte is complete,
each ion makes a definite contribution of its own towards the
molar conductivity of electrolyte, irrespective of
1
13
14.
15.
16.
17.
the nature of the other ion with which it is associated.
1
1
1
1
● Ωo = ν+ λ˚+ + ν– λ˚–
m
1
OR
● B
● Dilution causes the degree of dissociation/ionization of B to
increase, resulting in greater number of ions.
● The reactions which have actual order higher than 1, but
under certain conditions behave like a first order reactions.
● Acidic hydrolysis of ethyl acetate or sucrose.
18.
For a first order reaction, k = 0.693 = = 0.693 = 0.01 min−1
t0.5
69.3
t = 2.303 log
R0
k
=
19.
2.303 log
100
0.01
R
0.01
(a)
(b)
(a)
(b)
21
(a)
(b)
22.
= 230.3 × 0.6990
t = 160.9 min
(Half mark to be deducted for not writing or writhing wrong unit)
Ionization isomerism
Coordination isomerism
An optically inactive mixture of two enantiomers in equal
proportions.
A carbon atom attached to four different atoms or group of atoms.
OR
The boiling points of isomeric alkyl halides decrease with
1
1
½
½
½
½
1
1
1
1
branching because of the weakened van der Waal’s forces.
1
It is because para-isomers fit in the crystal lattice better than
ortho- and meta-isomers.
1
SECTION C
MB of solute, C6H8O6 = (6×12) + (8×1) + (6×16)
= 176 g mol−1
½
WB
= ∆Tf × MB × WA
½
= 1.5 ×176 ×75
1
Kf × 1000
3.9 ×1000
23
.
1
20
= 2.303 log 5
20
1
= 5.08 g
The IUPAC name of the complex is tetracyanidonickelate (II).
(a)
It uses dsp2 hybridization.
1
1
1
The strong CN− ligands cause all d8 electrons to pair in the 3d
(
b orbital (spin-pairing).
) Having same kind of ligands.
1
(
c
)
(
a
)
1
½
24.
(
b
)
½
(
c
)
1
● Mechanism of dehydration of ethanol: H2SO4 →
H+ + HSO4−
½
½
2
5
½
½
1
● Ethoxyethane (diethyl ether).
1
26
a)
b)
R—CONH2 + Br2 + 4NaOH → R—NH2 + Na2CO3 + 2NaBr + 2H2O
1
c)
R—NH2 + CHCl3 + 3KOH → R—NC + 3KCl + 3 H2O
1
Amide
1º amine
1º amine
alkyl isocyanide
OR
a)
C6H5NH2 < C6H5CH2NH2 < CH3NH2
b)
N,N-Dimethylbenzeneamine
c)1
Aniline, a Lewis base, forms salt with catalyst AlCl3,
a Lewis acid.
27
28
(a)Benzoic acid and benzophenone
Benzoic acid gives brisk effervescence of CO2 with NaHCO3 where as Benzophenone
donot liberate CO2
(b) Formaldehyde and benzaldehyde
Formaldehyde gives Brick red ppt with Fehling’s solution, where as Benzaldehyde don’t
give brick red ppt.
(c ) Ethanol and phenol
Phenol gives violet colour with ferric chloride , where as ethanol don’t form.
Loss of biological activity of a protein when protein is subjected to change
in Temperature or pH is called denaturation of protein.
Ex Boiling of egg or curdling of milk.
Amino acids which are not synthesized bybody, but supplied through diet
1
1
1
1x3
2+1
are called essential amino acids.
29
30
i) It depends on no of moles not on the nature of
solute added.
ii) 5
iii) 3
OR
Correct answer.
a. Ductless
2
b. Both not stored in body
1
c. Hormones formed communication between
cells in our body.
OR
Pituitary gland
d. Correct difference
1
1
1
1
1
SECTION E
31
a) Correct reaction.
b) Sn
c) E˚
= E˚
cell
cathode
– E˚
c
anode
= 0.799 − (−0.136) = 0.935 V
d
d) Salt- bridge-Maintain electrical neutrality.
Ecell = Eo
cell
– 0.059 log [C] [D]
[A]a [B]b
n
Sn(s) + 2Ag+(aq) → Sn2+(aq) + 2Ag(s) Therefore, n = 2
= 0.935 –
0.059/2
log 0.02
(0.1)2
= 0.935 – 0.059 log 2
2
= 0.935 – (0.0295 × 0.3010)
= 0.935 – 0.0088
= 0.9262 V
(Half mark to be deducted for not writing or writhing wrong unit)
e) Spontaneous
f) No
It has fully-filled d10 configuration, so no d-d transition is possible.
32
It has six unpaired electrons, so it forms extensive
metallic/covalent bonds.
It achieves stable noble gas configuration after losing three
electrons.
They have reasonably large void where a small-sized element like
hydrogen, boron or carbon can be trapped.
They don’t have unpaired electrons in their (n−1)d orbital in their
elemental form or in their common oxidation states.
OR
● Lanthanide contraction is the steady decrease in the atomic and ionic
sizes of lanthanide elements.
● Its major cause is the inability of inner 4f electrons to screen the outer 6s
electrons.
● Its consequences include comparable atomic sizes of 4d and 5d series
elements and regular decrease in basic strength
from La(OH)3 to Lu(OH)3.
1
1
+
½
It is because Ce4+ gains one electron to convert to more stable
Ce3+.
2MnO4− + H2O + I− → 2MnO2 + 2OH− + IO3−
(½ marks to be deducted if the reaction is not balanced)
● A
:
C6H5COCH3
33
● B
● C
● D
E
:
:
:
:
C6H5CH2CH3
C6H5COOH
C6H5COONa
CHI3
OR
CH4
CH3CH(Br)COOH
C6H5COCl
d) By Tollens test
e) By Iodorm reaction
1
1
1
1
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
CHEMISTRY THEORY (043)
SAMPLE PAPER NO- 2
BLUE-PRINT
CHEMISTRY (043)
Class: XII
S.No Chapters
MCQ
1
Mark
1
SOLUTIONS
2
ELECTRO CHEMISTRY
1(1)
3
CHEMICAL KINETICS
2(2)
4
d BLOCK Elements
2(2)
A/R
1
Mark
VSA
SA
2
3
Marks Marks
2(2)
1(3)
1(3)
1(1)
Case
study
question
4 marks
LAQ
Total
Marks
5
MARKS
70
7
1(4)
9
1(5)
1(5)
Coordination
1(3)
1(4)
7
7
7
5
compounds
HALO ALKANES
1(1)
1(2)
1(3)
6
1(3)
6
1(3)
8
1 (3)
6
6
AND HALO ARENES
ALCOHOLS,
2(2)
7
1(1)
PHENOLS & ETHER
CARBONYLS &
2(2)
8
1(2)
1(1)
CARBOXYLIC ACIDS
9
AMINES
1(1)
10
BIOMOLECULES
1(1)
1(2)
1(1)
1(5)
7
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII
CHEMISTRY THEORY (043)
Max. Marks:70
Time: 3:00 hours
SAMPLE PAPER NO-2
General Instructions:
Read the following instructions carefully.
(a) There are 33 questions in this question paper with internal choice.
(b) SECTION A consists of 16 multiple -choice questions carrying 1 mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7 short answer questions carrying 3 marks each.
(e) SECTION D consists of 2 case - based questions carrying 4 marks each.
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory. (h) Use of log tables and calculators is not allowed.
SECTION A
The following questions are multiple -choice questions with one correct answer. Each
question carries 1 mark. There is no internal choice in this section.
S.N.
1.
QUESTIONS:
Which of the following solutions of KCl will have the highest value of
conductivity?
a) 0.5 M
b) 0.01M
c) 0.1M
MARKS
1
d) 1.0 M
2.
1
Above shown Acetal is formed by the reaction between A &B in the presence of
dry HCl. Identify A and B.
3.
4.
5.
a) A is Methanal, B is Methanol
b) A is Methanal, B is Ethanol
c) A is Ethanal, B is Methanol
d) A is Ethanal, B is Ethanol
Which one of the following is caused due to the deficiency of Vitamin B1?
1
a) Convulsions
b) Beri-Beri
c) Cheilosis
d) Sterility
What is the IUPAC name of the Ketone A, which undergoes Clemmensen
1
reduction to form Ethyl benzene?
a) Propan-2-one
b) 1-Phenylethanone
c) 3-Methylbut-2-en-one
d) Butan-2-one
Which one of the following is an incorrect statement with respect to SN1 and SN2 1
mechanism for alkyl halides?
a) A strong nucleophile in an aprotic solvent increases the rate of SN2 reaction.
b) Competing reaction for an SN2 reaction is rearrangement.
6.
7.
8.
9
10.
11.
12.
13.
c) SN1 reactions proceed via carbocation intermediate.
d) A weak nucleophile and a protic solvent increase the rate or favours SN1
reaction.
Match the properties with the elements of 3d series:
(i)Element with highest M.P.
(p)Cr3+
(ii)Element showing +3 oxidation state
(q)Cr
(iii)Most stable ion in aqueous solution
(r) Fe
(s) Sc
(a) (i) (q), (ii) (s),(iii) (p)
(b) (i) (s),(ii) (q),(iii) (r)
(c ) (i) (q), (ii) (p), (iii) (r)
(d) (i) (p),(ii) (q),(iii) (r)
Which of the following is not correct about the order of a reaction:
(a) The order of a reaction can be a fractional number.
(b) Order of reaction is experimentally determined quantity.
(c ) The order of a reaction is always equal to sum of the stoichiometric
coefficients of reactant in the balanced chemical equation for a reaction.
(d) The order of a reaction is the sum of the powers of molar concentrations of
the reactants in the rate law expression.
Which of the following will be most stable diazonium salt RN2+X--?
(a) CH3CH2N2+X-(b) C6H5N2+X + -(c ) CH3N2 X
(d) C6H5CH2N2+X-The aromatic compounds having formula C7H8O which are easily identifiable by
FeCl3 solution test are:
(a) o-cresol &benzyl alcohol
(b) m-cresol & p-cresol
(c ) o-cresol & p- cresol
(d) methyl phenyl ether and benzyl alcohol
The decomposition of NH3 on platinum surface is zero order reaction. What is the
rate of production of H2 If k = 2.5 × 10—4 mol/L/Sec?
(a) 7.5 × 10—4 mol/L/Sec
(b) 6.5 × 10—4 mol/L/Sec
(c ) 5.7 × 10—4 mol/L/Sec
(d)7.1 × 10—4 mol/L/Sec
Why ortho- nitrophenol is less soluble in water than p—and m—nitrophenol?
(a) Due to intramolecular H- bonding (b) Due to intermolecular H-bonding
(c ) M.P. of o-nitrophenol lower than p- and m- nitrophenol
(d) o- nitrophenol is more steam volatile.
The trend of which property is represented by the following graph?
1
1
1
1
1
1
1
(a) Ionization enthalpy
(b) Atomic radii
(c ) Melting point
(d) Enthalpy of atomization
Given below are two statements labelled as Assertion (A) and Reason (R):
1
Assertion: Phenol on oxidation with chromic acid gives benzoquinone.
Reason: Pure phenol is colourless but turn pink due to oxidation to phenoquinone.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
14.
15.
16
(c) A is true but R is false.
(d) A is false but R is true.
Given below are two statements labelled as Assertion (A) and Reason (R):
Assertion: Carboxylic acids are more acidic than phenol.
Reason: Phenols are ortho and para directing.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Given below are two statements labelled as Assertion (A) and Reason (R):
Assertion: Albumin is globular protein.
Reason: Polypeptide chain coils around to give a straight chain.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Given below are two statements labelled as Assertion (A) and Reason (R):
Assertion: Electrolysis of NaCl solution gives chlorine at anode instead of O2.
Reason: Formation of oxygen at anode requires overvoltage.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
1
1
1
SECTION: B
This section contains 5 questions with internal choice in one question. The
following questions are very short answer type and carry 2 marks each.
17.
18.
19.
20.
(i) Gas (A) is more soluble in water than Gas (B) at the same temperature. Which
one of the two gases will have the higher value of KH (Henry’s constant) and
why?
(ii) In non-ideal solution, what type of deviation shows the formation of
maximum boiling azeotropes?
Calculate the mass of ascorbic acid (vitamin C, C6H8O6) to be dissolved in
75 g of acetic acid to lower its melting point by 1·5°C.
(Kf for CH3COOH) = 3·9 K kg mol-1, molar mass of C6H8O6 is 176 g/mol )
a) Arrange the following compounds in order of increasing boiling point.
Bromomethane, bromoform, chloromethane, dibromomethane
b) The treatment of alkyl chloride with aq. KOH leads to formation of alcohol but
in presence of alcoholic KOH, alkenes are the major products. Explain why?
a) Propanone is less reactive than ethanal towards addition of HCN. Why?
b) Write the structure of product will be formed on reaction of propanal with
2-methylpropanal in the presence of NaOH?
(OR)
a) Convert Ethylbenzene into benzoic acid
b) Convert Acetophenone into benzoic acid
1
1
2
1
1
1
1
1
1
21.
22.
23.
How are the following conversions carried out :
(a) Aniline to p-hydroxyazobenzene
(b) Ethanoyl chloride to Ethanenitrile.
SECTION: C
This section contains 7 questions with internal choice in one question. The
following questions are short answer type and carry 3 marks each.
Answer any three?
a) Write the formula for the following coordination compound:
Amminebromidochloridonitrito-N- platinate(II)
b) FeSO4 solution mixed with (NH4)2SO4 solution in 1:1 molar ratio gives the test
of Fe3+ but CuSO4 solution mixed with aqueous ammonia in 1:4 ratio does not
give test of Cu2+ ion. Explain why?
c) Define Ambidentate ligand with suitable example?
d) [NiCl4]2- is paramagnetic, while [NiCO4] is diamagnetic though both are
tetrahedral. Why?
1
a) What is necessity to use a salt- bridge in a Galvanic cell.
b) Calculate 𝛬mº for CaCl2 from the following data:
1
𝛬mº (Ca2+) = 119.0 S cm2 mol-1, 𝛬mº (Cl–) = 76.3 S cm2 mol-1
c) The electrical resistance of a column of .05 M NaOH solution of diameter
1 cm and length 50 cm, is 5.55 × 10 3 Ohm. Calculate its conductivity.
24.
25.
26.
27.
28
Write the structure and IUPAC name of product formed
when
(a) Phenol is treated with NaOH followed by heating with CO2 at 400 K at
4 to 7 atmospheres.
(b) Sodium ethoxide reacts with Bromomethane.
(c) Phenol reacts with concentrated nitric acid and conc. H2SO4.
An organic compound (A) (molecular formula C8 H16O2) was hydrolysed with
dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation
of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene. Write
equations for the reactions involved.
1
1
1
1
1
1
1
1
1
3
(i) Arrange the following compounds in an increasing order of basic strength :
C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2
1
Give a chemical test to distinguish between each of the following pairs of
compounds :
(ii) Ethylamine and Aniline
(iii) Aniline and Benzylamine
Write the mechanism of the following reaction:
1
1
3
(i) On mixing liquid X and liquid Y, volume of the resulting solution decreases.
What type of deviation from Raoult’s law is shown by the resulting solution?
What change in temperature would you observe after mixing liquids X and Y?
(ii) What happens when we place the blood cell in water (hypotonic solution)?
Give reason.
SECTION: D
2
1
The following questions are case -based questions. Each question has an
internal choice and carries 4 (1+1+2) marks each. Read the passage carefully
and answer the questions that follow.
29.
The stability of complex in solution refers to degree of association between the two
species involved in the state of equilibrium. The magnitude of the equilibrium constant
(stability or formation) for the association, quantitatively expresses the stability. If
complex is formed in steps, then the stepwise and overall stability constant is related as
follows—
The addition of four amine groups to copper shows a pattern found for most formation
constants, in which the successive stability constant decreases. The instability constant
or the dissociation constant of coordination compound is defined as reciprocal of
formation constant β 4.
According to the given paragraph, answer the following questions:
(a) Why is stability constants of cyanides are higher than complexes with NH3 as
a ligand?
(b) Which of the complexes given in table is least stable? Why?
(c) (i) Why is [Fe(CN)6 ] 3– is more stable than [Fe(CN)6 ] 4–?
(ii) Why is [Ag(NH3 )2 ] + is less stable than [Cu(NH3 )4 ] 2+?
OR
(d) Calculate the overall complex dissociation equilibrium constant for the
[Cu(NH3 )4 ] 2+ ion, given that for this complex β4=2*1013 .
30.
The standard electrode potentials are very important and we can extract a lot of
useful information from them. If the standard electrode potential of an electrode is
greater than zero then its reduced form is more stable compared to hydrogen gas.
Similarly, if the standard electrode potential is negative then hydrogen gas is more
stable than the reduced form of the species. It can be seen that the standard
31.
electrode potential for fluorine is the highest in the electrochemical series
indicating that fluorine gas (F2) has the maximum tendency to get reduced to
fluoride ions (F–) and therefore fluorine gas is the strongest oxidising agent and
fluoride ion is the weakest reducing agent. Lithium has the lowest electrode
potential indicating that lithium ion is the weakest oxidising agent while lithium
metal is the most powerful reducing agent in an aqueous solution. It may be seen
that as we go from top to bottom in in electrochemical series the standard
electrode potential decreases and with this, decreases the oxidising power of the
species on the left and increases the reducing power of the species on the righthand side of the reaction.
(a) Write cell reaction of Zn and Cu cell.
1
(b) E0 reduction of three metals A, B, C are respectively + 0.5 V, - 3.0 V, -1.2 V
write the decreasing order of reducing power of these metals.
1
(c) A student prepared 1 molar aqueous solution of silver nitrate and stirred the
solution with copper spoon. Point out if he has committed any mistake.
2
(OR)
Silver articles gets tarnished gradually due to the formation of Ag2S layer. In
order to remove the tarnish a student placed the silverware in aqueous solution of
sodium chloride taken in aluminum vessel. Will he succeed or not? Justify.
E0 Al+3/Al = - 1.66 V and
E0 Ag2S(s)/Ag(s) = - 0.71 V
SECTION: E
The following questions are long answer type and carry 5 marks each. All
questions have an internal choice.
ATTEMPT ANY FIVE OF THE FOLLOWING:
1X5=5
(a) Of the d4 species, Cr2+ is strongly reducing whereas manganese (III) is
strongly oxidising. Why?
(b) How do you prepare K2MnO4 from MnO2?
(c) Complete the following chemical equation:
Cr2O72– + 6Fe2+ + 14H+ →
(d) How would you account for the following: Zr (Z = 40) and Hf (Z = 72) have
almost identical radii.
(e) What are different oxidation states exhibited by lanthanoids?
(f) Which of following cations are colored in aqueous solutions and why?
Sc3+, V3+, Ti4+, Mn2+ (At. No. Sc = 21, V = 23, Ti = 22, Mn = 25)
(g) State reasons for the Cu (I) ion is not stable in an aqueous solution.
32.
(a) Explain the following terms:
(i) Rate of a reaction
(ii) Activation energy of a reaction
(b) The decomposition of phosphine, PH3, proceeds according to the following
equation:
4 PH3 (g) → P4 (g) + 6 H2 (g)
It is found that the reaction follows the following rate equation :
1
1
3
33.
Rate = K [PH3].
The half-life of PH3 is 37.9 s at 120° C.
(i) How much time is required for 3/4th of PH3 to decompose?
(it) What fraction of the original sample of PH3 remains behind after 1 minute?
OR
(a) Explain the following terms :
(i) Order of a reaction
(ii) Molecularity of a reaction
(b) The rate of a reaction increases four times when the temperature changes from
300 K to 320 K. Calculate the energy of activation of the reaction, assuming that
it does not change with temperature. (R = 8.314 J K-1 mol-1)
(a) Why water-soluble vitamins must be supplied regularly in the diet? Give one
example of it.
(b) Differentiate between the following:
(i) Essential and non-essential amino acids.
(ii) Fibrous and globular proteins.
(c) Which one of the following is a polysaccharide:
Starch, Maltose, Fructose, Glucose
OR
(a) What one difference between a-helix and P-pleated sheet structure of protein.
(b) Write the name of the disease caused by the deficiency of Vitamin B12.
(c) Deficiency of which vitamin causes scurvy?
(d) What type of linkage is responsible for the formation of proteins?
(e) Write the product formed when glucose is treated with HI.
2
3
2
2
1
1
1
1
1
1
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII
CHEMISTRY THEORY (043)
GROUP -4 (James Chadwick) QP-2
CLASS: XII
MARKING SCHEME
SECTION A
S.N.
QUESTIONS:
MARKS
1.
D
1
2.
D
1
3.
B
1
4.
B
1
5.
B
1
6.
A
1
7.
C
1
8.
B
1
9
A
1
10.
A
1
11.
A
1
12.
C
1
13.
B
1
14.
B
1
15.
C
1
16
A
1
17.
i) B
ii) large negative deviation.
1
1
18.
½
½
1
19.
a) bromoform >dibromethane > bromomethane > chloromethane (Decreasing order)
b) Alcoholic solution of KOH contains alkoxide ion which being stronger base eliminates
a molecule of HCl from alkyl halide to form alkene. ( Any suitable explanation)
1
1
20.
a) Due to steric and electronic reasons
b) 2,4-Dimethylpent-2-en-al
1
1
OR
a)
OR
1
b)
1
21.
Correct route of conversions
1
1
22.
a) [Pt (NH3) Br Cl (N02)]–
1
b) FeSO4 forms double salt whereas CuSO4 forms complex ion.
c) Correct definition with suitable example.
OR
23.
(b) In [NiCl4]2- , Cl is weak field ligand so no pairing takes place. Hence it is
paramagnetic whereas in [Ni (CO)4], CO is strong field ligand, so pairing of electron
takes place in d-orbital. Hence it is diamagnetic. a) It connects the solution of two half cells, thus completes the cell circuit.
( Any suitable reason).
1
1
1
b)
𝛬mº (CaCl2) = 𝛬mº (Ca2+) + 2 X [𝛬mº (Cl–)]
1
𝛬mº (CaCl2) = [119.0 + 2 X 76.3] S cm2 mol-1
𝛬mº (CaCl2) = [119.0 + 152.6] S cm2 mol-1 ,𝛬mº (CaCl2) = 271.6 S cm2 mol-1
24.
25.
c ) FORMULA, CALCULATION and Answer , 1.148 x 10—2 S/cm
(a) Correct structure & IUPAC name
(b) Correct structure & IUPAC name
(c) C6H5OH + CONC. HNO3 ( nitration) → Picric acid
1
1
1
1
3
26.
(a)Correct order.
(b) Azo dye test
(c )Azo dye test
1
1
1
27.
KCN is a resonance hybrid of the following two contributing structures
3
Thus, CN– ion is an ambident nucleophile. Therefore, it can attack the “carbon atom of
C-Br bond in n-BuBr either through C or N. Since C – C bond is stronger than C – N
bond, therefore, attack occurs through C to form n-butyl cyanide.
28
i)
ii)
Negative solution, cools down
Cells will shrink
3
SECTION: D
29.
30.
a) strong ligand
b) No 9
c) i)+3 oxidation state more stable than +2
ii) correct answer
(a) Zn + Cu+2 → Zn+2 + Cu
(b) B > C> A
1
1
(c) It is not safe to stir AgNO3 solution with copper spoon because reduction of Ag+ by Cu
2
is a feasible process.
(OR)
As E0cell is positive the reaction is feasible and he will succeed to get rid of tarnish from
silver ware.
SECTION: E
31.
2+
(a) Cr is reducing as its configuration changes from d4 to d3 , having a half-filled t2g
level. On the other hand, the change from Mn3+ to Mn2+ results in the half-filled (d5 )
configuration which has extra stability.
(b) 2MnO2 + 4KOH + O2 → 2K2MnO4 + 2H2O
(c) Cr2O72– + 14 H+ + 6 Fe2+ → 2 Cr3+ + 6 Fe3+ + 7 H2O
(d) due to lanthanoid contraction 4d to 5d size decreases
(e) +2, +3, +4
(f) V3+, Mn2+ presence of unpaired electrons.
(g) because hydration enthalpy of Cu2+ is higher than that of Cu+ . It compensates the second
ionisation enthalpy of Cu involved in the formation of Cu2+ ions.
33
a) It excreted through urine. Vit-C
b) i)Essential amino acids are not made by the human body and must instead be acquired
from our diet. Non-essential amino acids, by contrast, are synthesized by the human
Any five
answers
1 mark
each
body.
ii) Fibrous proteins are generally composed of long and narrow strands and have structural
role Globular proteins generally have a more compact and rounded shape and have
functional roles
c) Starch
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
SAMPLE PAPER - 03
CHEMISTRY THEORY (043)
BLUE PRINT
General Instructions:
(a) There are 33 questions in this question paper with internal choice.
(b) SECTION A consists of 16 multiple -choice questions carrying 1 mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7 short answer questions carrying 3 marks each.
(e) SECTION D consists of 2 case - based questions carrying 4 marks each.
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory.
(h) Use of log tables and calculators is not allowed.
S.
NO.
Chapter
1
Solution
2
Electrochemistry
3
9
Chemical
Kinetics
d and f - Block
elements
Coordination
compounds
Haloalkanes
and
Haloarene
s
Alcohols,
Phenols
and Ethers
Aldehydes,
Ketones
an
d Carboxylic
acids
Amines
10
Biomolecules
4
5
6
7
8
MCQ
AR
Section
B
VSA
1 (1)
1 (1)
*
*
*
1 (5)
3 (7)
2 (2)
*
*
1 (3)
1(4)
*
4 (9)
1 (1)
1 (1)
1(2)
1 (3)
*
*
4 (7)
1(1)
1 (1)
*
*
*
1 (5)
3 (7)
1 (1)
*
1 (2)
*
1(4)
*
3 (7)
2 (2)
1(1)
*
1 (3)
*
*
4 (6)
1 (2)
1 (3)
*
*
3 (6)
1 (2)
*
*
1 (5)
3 (8)
Section A
Total
Section
C
SA
Section
D
Case
based
Section
E
LA
Total
*
1 (1)
*
1 (1)
1 (1)
*
1 (2)
1 (3)
*
*
3 (6)
1 (1)
*
*
2 (6)
*
*
3 (7)
5 (10)
7 (21)
2 (8)
3 (15)
33 (70)
16 (16)
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
SAMPLE PAPER - 03
CHEMISTRY THEORY (043)
Max.Marks:70
Time:3 Hours
Read the following Instructions carefully.
(a) There are 33 questions in this question paper with internal choice.
(b) SECTION A consists of 16 multiple –choice questions carrying1mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7short answer questions carrying 3 marks each.
(e) SECTION D consists of 2case-based questions carrying 4marks each.
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory.
(h) Use of log tables and calculators is not allowed.
SECTION-A
The following questions are multiple –choice questions with one correct answer. Each question
carries 1 mark. There is no internal choice in this section.
1
Solubility of gases in liquids decreases with rise in temperature because dissolution
[1]
is an:
(a) Endothermic and reversible process.
(b) Exothermic and reversible process.
(c) Endothermic and irreversible process.
(d) Exothermic and irreversible process.
2
Which of the following is a non-reducing sugar ?
(a)Glucose
3
(b)Sucrose
(c)Maltose
[1]
(d)Lactose
The atomic number of the element having magnetic momentum is equal to1.7B
Minits+2 oxidation state is:
(a) 24
(b)25
(c)26
(d) 29
[1]
4
For a reaction ,the energy of activation is zero. The value of rate constant at 300K,
if k = 1.6×106s−1at 280 K is:
(a)zero
(b)6.4×106s−1
(c)1.6×106s−1
(d)3.2×106s−1
[1]
5
6
Which of the following shows structure of allylic alcohol?
[1]
(i)CH2=CH-CH2OH
(ii)CH2=CH-OH
(iii)CH2=CH-CH(CH3)-OH
(iv)CH2=CH-C(CH3)2-OH
(a)(i),(iii)and(iv)
(b)(i),(ii)and(iv)
(c)(ii),(iii)and(iv)
(d)(i),(ii),(iii)and(iv)
Arrange the following compounds in decreasing order of pKb values:
[1]
C2H5NH2,(C2H5)2NH,C6H5NHCH3,C6H5NH2
(a) C2H5NH2 >(C2H5)2NH
(b) C6H5NHCH3
(c) C6H5NH2
>C6H5NH2
>C6H5NHCH3
(d) (C2H5)2NH>
7
>C6H5NH2
>C6H5NHCH3
>(C2H5)2NH>C2H5NH2
>C2H5NH2>(C2H5)2NH
C2H5NH2>C6H5NHCH3>C6H5NH2
How many moles of AgCl will be precipitated when an excess of AgNO3 is added to
[1]
a molar solution of [CrCl(H2O)5]Cl2?
(a) 6moles
8
9
(b) 8moles
(c) 3 moles
(d) 2moles
Choose the correct IUPAC name for
[1]
(a)3-Bromo-2-methylpropene
(b)1-Bromo-2-methylbut-2-ene
(c)4-Bromo-3-methylpent-2-ene
(d)3-Bromo-2-methylbut-1-ene
Thevariationofmolarconductivitywithconcentrationofanelectrolyte(X)inaqueous
solution is shown in the given figure
The electrolyte X is:
(a) HCl
(b) NaCl
(c)KNO3
(d)CH3COOH
[1]
10
At 25°C,the molar conductance at infinite dilution for the strong electrolytes NaOH,
[1]
NaCl and BaCl2are 248 × 10–4, 126 × 10–4 and 280 × 10–4 Sm2mol–1 respectively.
Λ0mBa(OH)2inSm2mol–1is
11
(a)52.4×10–4
(b)524× 10–4
(c)402×10–4
(d)262× 10–4
2-Bromo pentane is heated with potassium ethoxide in ethanol.The major product
[1]
obtained is
12
(a)2-ethoxypentane
(b)pentene-1
(c)cis-pent-2-ene
(d)trans-pent-2-ene
Study the given reaction and identify the process which is carried out..
[1]
(a) It is used for purification of aldehydes and ketones
(b) It is used to distinguish aldehydes from ketones
(c) It is used to prepare cyclic aldehydes and ketones
(d) It is used to study polar nature of aldehydes and ketones
13
Given below are two statements labeled as Assertion(A)and Reason(R)
[1]
Assertion: Molarity of the solution changes with temperature.
Reason: Molarity is a colligative property.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
14
Given below are two statements labeled as Assertion(A)and Reason(R)
Assertion:Alkyl iodide can be prepared by treating alkyl chloride with NaI in
acetone.
Reason: NaCl is soluble in acetone but NaI is not.
Select the most appropriate answer from the options given below:
(e) Both A and R are true and R is the correct explanation of A.
(f) Both A and R are true but R is not the correct explanation of A.
(g) A is true but R is false.
(a) A is false but R is true.
[1]
15
Given below are two statements labeled as Assertion(A)and Reason(R)
[1]
Assertion:Rate of reaction changes with temperature but rate constant does not.
Reason:Rate of reaction depends upon concentration of reactants but rate
constant does not depend upon the concentration of reactants.
Select the most appropriate answer from the options given below:
(h) Both A and R are true and R is the correct explanation of A.
(i) Both A and R are true but R is not the correct explanation of A.
(j) A is true but R is false.
(a) A is false but R is true.
16
Given below are two statements labeled as Assertion(A)and Reason(R)
[1]
Assertion:Separation of Zr and Hf Is difficult.
Reason:Because Zr and Hf lie in the same group of the periodictable. Select
the most appropriate answer from the options given below:
(k) Both A and R are true and R is the correct explanation of A.
(l) Both A and R are true but R is not the correct explanation of A.
(m) A is true but R is false.
(d) A is false but R is true.
SECTION - B
This section contains 5 questions with internal choice in one question.The
following questions are very short answer type and carry 2 marks each.
17
A chloride of fourth group cation in qualitative analysis gives a green coloured
[2]
complex [A] in aqueous solution which when treated with ethane –1, 2 – diamine
(en) gives pale-yellow solution [B] which on subsequent addition of ethane –1,2–
diamine turns to blue/purple [C] and finally to violet [D]. Write the structures of
Complexes [A],[B],[C]and[D].
18
[2]
(a) Predict the order of the reaction.
(b) What is the slope of the curve?
19
Explain the mechanism of dehydration steps of ethanol:
[2]
Or
Name the reagents used in the following reactions:
20
(i)
Bromination of phenol to2,4,6-tribromo phenol
(ii)
Butan-2-one to Butan-2-ol
(iii)
Friedel–Crafts alkylation of anisole
(iv)
Oxidation of primary alcohol to carboxylic acid.
Account for the following:
(i)
[2]
Although–NH2 is o/p directing group, yet aniline on nitration gives a
significant amount of m-nitroaniline.
(ii)
21
Aniline does not goFriedelCrafts reaction.
Write the products of the following reactions:
[2]
(i)
(ii)
SECTION- C
This section contains 7questions with internal choice in one question. The following
questions are short answer type and carry 3 marks each.
22
Calculate e.m.f.of the following cell at 298K:
[3]
2Cr(s)+3Fe2+(0.1M)→2Cr3+(0.01M)+3Fe(s)
Given:E0(Cr3+∣Cr)=−0.74V,E0(Fe2+∣Fe)=−0.44V
23
Attempt any two questions from following:
(a) Write the structure of anisomer of compound C4H9B rwhich is most reactive
towards SN1reaction.
(b) What happens when CH3Br is treated with KCN?
(c) Why does p-dichlorobenzene have a high er melting point than its o- and
m- isomers?
[3]
24
The data given below is for the reaction,
[3]
2N2O5(g)→4NO2(g)+O2(g)at298K:
Determine for this reaction:
(i) Order of reaction
(ii) Rate constant
(iii) Rate law.
25
Write the structures of A, B and C in the following reactions:
[3]
26
(a)Write the name of two monosaccharides obtained on hydrolys is of lactose sugar.
[3]
(b)Name any one fat soluble vitamin,its sources and the diseases caused due to
its deficiency in diet.
27
(a)Which of the following isomers is more volatile:
[3]
o-nitrophenol or p-nitrophenol?
(b)How would you obtained
(i) Picric acid (2,4,6-trinitro phenol)from phenol.
(ii) 2-Methyl propenefrom2-methylpropanol?
28
(a) What is the structural difference between a nucleoside and a nucleotide?
(b) What happens when D-glucose is treated with HI?
(c) Give two examples of globular proteins.
[3]
SECTION-D
The following questions are case –based questions .Each question has an
Internal choice and carries 4(1+1+2) marks each .Read the passage carefully
and answer the questions that follow.
29
Electrochemistry playsa very importantpart in ourdaily life. Electrochemical cell
[4]
converts chemical energy of redox reaction into electricity. Mercury cell, Drycells
are primary cells whereas Ni—Cd cell, lead storage battery are secondary
Cells..A 38% solution of sulphuric and is used in lead storage batter..Its density is
1.30gmL–1.The battery holds 3.5L of the acid. During the discharge of the battery, the
density of H2SO4 falls to 1.14 g mL–1 (20% solution by mass) (Molar mass of H2SO4 is
98 g mol–1).
(i) Which type of cell is Mercury cell ?
(ii) How much electricity in Faraday is required to carry out the reduction of one mole
of PbO2?
(iii) Write the reactions taking place at cathode and anode in lead storage battery
when the battery is in use. What happens on charging the battery?
Or
(iii)Mention the reactions occurring at (i) anode, (ii) cathode,during working of a
Mercury cell. Why does the voltage of a mercury cell remain constant during ts
operation?
30
As in case of organic compounds, coordination compounds also show two types of
isomerism viz. structural isomerism and stereo isomerism. There are four types of
structural isomerism shown by coordination compounds viz. ionization isomerism,
hydrate isomerism, linkage isomerism and coordination isomerism. Similarly, there
are two types of stereo isomerism viz. geometrical isomerism and optical isomerism.
Geometrical isomerism is shown by square planar as well as octahedral complexes
whereas optical isomerism is shown by octahedral complexes.
(i) Write the coordination isomer of[Cu(NH3)4][PtCl4].
(ii) Name the ionization isomer of[Cr(H2O)5Br]SO4.
(iii) Indicate the types of isomerism exhibited by the following complexes:
(a) [Co(NH3)5(NO2)]2+
(b) [Co(en)3]Cl3
Or
[4]
(iii) Draw the structures of:
(a) Cis – dichlorido tetra cyano chromate(III)
(b) Mer – triamminetrichloridocobalt(III)
SECTIONE - E
The following questions are long answer type and carry 5 marks each.All
questions have an internal choice.
31
(i) Arrange the following compounds in increasing order of their property as
[5]
indicated:
(a) Benzoic acid,4-Nitrobenzoic acid,3,4-Dinitrobenzoic acid,4-Methoxybenzoic
acid (acid strength)
(b) Propanal,Ethanal,Propanone,Butanone.(reactivity in nucleophilic.
addition reactions)
(ii) Illustrate the following name reactions giving a chemical equations in each case:
(a) Hell-Volhard-Zelinsky reaction
(b) Cannizzaro’s reaction
(iii) Although phenoxide ion has more resonating structures than carboxylate ion, the
carboxylic acid is a stronger acid than phenol. Explain
Or
(i) How will you bring about the following conversions in not more than two steps?
(a) Benzoicacid to Benzaldehyde
(b) Propanone toPropene
(c) Benzene to m-Nitroacetophenone
(ii) Write the chemical test to distinguish:
(a) Propanal and propanone
(b) Benzaldehyde and acetophenone
32
How would you account for the following::
[5]
(a)
Highest fluoride of Mn is MnF4 where as the highest oxide is Mn2O7.
(b)
(c)
Cu2+salts are coloured,while Zn2+ salts are white.
The members of the actinoid series exhibita larger number of oxidation
states than the corresponding members of the lanthanoid series.
(d)
With the same d-orbital configuration(d4),Cr2+ is a reducing agent while
Mn3+ is an oxidising agent.
(e)
Transition metals and their compounds act as catalyst.
Or
(i) Which metal in the first transition series (3d-series) exhibits+1oxidation state
most frequently and why?
(ii) Write the electronic configuration of Ce3+ ion, and calculate the magnetic moment
on the basis of ‘spin-only’ formula. [Atomic no. of Ce = 58]
(iii) How does the acidified potassium permanganate solution react with
(a) iron(II)ions and(ii)oxalic acid?
Write the ionic equations for the reactions.
33
(i) Calculate the amount of KCl which must be added to1kg of water so that the
freezing point is depressed by 2 K (the Kffor water = 1.86 K kg mol–1).
(ii) Define azeotropes. What type of azeotrope is formed by negative deviation from
Raoult’s law? Give an example.
Or
(i) A solution containing15gurea(molarmass= 60gmol–1) per litre of solutionin
water has the same osmotic pressure (isotonic)as a solution of glucose(molar
mass = 180 g mol–1) in water. Calculate the mass of glucose present in one
litre of its solution.
(ii) Define the term ‘osmotic pressure’. What is the advantage of using osmotic
pressure as compared to other colligative properties for the determination of
Molar masses of solutes in solutions?
[5]
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
SAMPLE PAPER - 03
CHEMISTRY THEORY (043)
SAMPLE PAPER 2023-24
CLASS-XII CHEMISTRY MARKING SCHEME
Q.No
VALUE POINTS
MARKS
1
(b) exothermic and reversible process
1
2
(b) Sucrose
1
3
(d) 29
1
4
(c) 1.6×106 s−1
1
5
(a) (i), (iii) and (iv)
1
6
(c) C6H5NH2
1
7
(d) 2 moles
1
8
(b) 1-Bromo-2-methylbut-2-ene
1
9
(d) CH3COOH
1
10 (b) 524 × 10–4
1
11 (d) trans-pent-2-ene
1
12 (a) It is used for purification of aldehydes and ketones.
1
13 (c) A is true but R is false.
1
14 (c) A is true but R is false.
1
15 (d) A is false but R is true.
1
16 (b) Both A and R are true but R is not the correct explanation of A.
1
17 A=[Ni(H2O)6]2+ B=[Ni(H2O)4(en)]2+
C=[Ni(H2O)2(en)2]2+ D=[Ni(en)3]2+
½ x4=2
18
(a) Zero order
(b) [R] = [R0] – kt
Slope = – k
2
> C6H5NHCH3 > C2H5NH2 > (C2H5)2NH
reaction.
19
2
Or
½
(i) Bromine water, (Br2(aq))
(ii) Lithium aluminium hydride, (LiAlH4) or H2/Ni
(iii) Alkyl halide in the presence of anhydrous aluminium chloride, CH3Cl and
AlCl3 (anhy.)
½
½
½
(iv) Acidified potassium permanganate
(i) 20 Although amino group is o, p- directing in aromatic electrophilic substitution
1
reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
Nitration is carried out in an acidic medium. In an acidic medium, aniline is
protonated to give anilinium ion (which is meta- directing). For this reason,
aniline on nitration gives a substantial amount of m-nitroaniline.
(ii)
It is because aniline is basic, can form adduct salt with AlCl3 due to
which it deactivates and electrophile cannot be generated
21 (i)
1
1
(ii)
1
22
1
1
1
23 (a)
1
(b)
1
(c) p-Dichlorobenzene has higher melting point than those of o-and m- isomers
because it is more symmetrical and packing is better in solid form. Hence, it has
stronger intermolecular force of attraction than o-and
m-isomers
1
1 +1+1
24
25
1
1
26 Lactose on hydrolysis gives -D-glucose and -D-galactose.
(a)
(b) Examples of fat-soluble vitamins are vitamin A and D (any one).
1
1+1
(i)
(ii)
27 o-nitrophenol
(a)
1
1
(b)
1
(a)
28
Nucleoside contains pentose sugar, and base whereas nucleotide contains
pentose sugar, base as well as phosphate group.
Nucleoside = Base + Sugar
Nucleotide = Base + Sugar + Phosphate.
1
(b)
1
(c) Haemoglobin, Insulin or any other correct example
½+½
29
(i) Primary cell
(ii) PbO2 + 4H++ 2e– + SO42– → PbSO4 + 2H2O
2 Faraday is required.
(iii)
1
1
1+1
Or
1+1
The cell potential remains constant during its life as the overall reaction does not
involve any ion in solution whose concentration can change during its use.
[Pt(NH3)4] [CuCl4]
30 (i)
(ii) pentaaquasulphatochromium(III) bromide
(ii)
1
1
(a) Linkage isomerism
(b) Optical isomerism
1 +1
Or
1 +1
(a)
(b)
(a) 4-Methoxybenzoic acid < Benzoic acid < 4-Nitrobenzoic acid
31 (i)
< 3,4-Dinitrobenzoic acid
(b) Ethanal < Propanal < Propanone < Butanone
(ii)(a) Cannizzaro’s reaction : Aldehydes which do not contain α -H atom undergo
disproportionation when heated with concentrated
(50 %) NaOH.
(b) Hell Volhard Zelinsky reaction: Carboxylic acids react with chlorine or
bromine in the presence of phosphorous to
give compounds in which α-hydrogen atom is replaced by halogen atom.
1+1
(iii) The negative charge rests on the electronegative O atom in carboxylate ion. The
presence of negative charge on an electronegative atom makes the ion more stable.
For the same reason RCOO– is more stable than the phenoxide ion where the
carbon has negative charge on it. For the above two reasons carboxylate ion is
more stable and has higher acidity than phenol.
Or
(i) Conversion:
(a)
(b)
(c)
(ii) (a) Propanal and propanone can be distinguished by their reactions with Tollens’
eagent. Propanal will form the silver mirror, but propanone does not react. Or any
other test – Iodoform/ Fehling test
(b) Benzaldehyde will form silver mirror, on treatment with Tollens’ reagent whereas
acetophenone will not show Tollens’ Test. Or any other test – Iodoform test
(i)
32(a) Manganese can form p𝜋 - d𝜋 bond with oxygen by utilising 2p-orbital of oxygen and 1
3d-orbital of manganese due to which it can show highest
oxidation state of +7. While with fluorine it cannot form such p𝜋 - d𝜋 bond thus, it can
show a maximum of +4 oxidation state.
(b) Zn2+has 3d10 configuration and no unpaired electrons, hence it is colourless.
Whereas in Cu2+state which has 3d93d9 configuration there is one unpaired electron
and it undergoes d-d transitions emiting colour so Cu2+ salts are blue in colour.
1
(c) Actinides exhibit larger oxidation states than lanthanides, because of the very
small energy gap between 5f, 6d and 7s subshells. Thus, the outermost electrons
get easily excited to the higher energy levels, giving variable oxidation states.
(d) Cr2+ has the configuration 3d4. It can lose electron to form 3d3 which has stable 1
configuration (as it has half -filled t2g level). Hence, it is reducing. On the other hand,
Mn3+ also has 3d4. configuration but it can gain electron to form
1 +1
(e)
Mn2+ which has stable 3d5 configuration.
Their ability to adopt multiple oxidation states, ability to adsorb the reactant(s) and
ability to form complexes.
Or
(i) Copper exhibits +1 oxidation state in its compounds. Electronic configuration of Cu ½ +½
in the ground state is 3d10 4s1. So, Cu can easily lose 4s1electron to
give a stable 3d10 configuration. Thus it shows +1 oxidation state.
(ii)
1+1
(iii)
(a)
(b)
1+1
33
(
i
)
(ii)
Azeotropes are the binary mixtures of solutions that have the same composition in
3 +2
liquid and vapour phases and that have constant boiling points. A maximum
boiling azeotrope is formed by solutions showing a large negative deviation from
Raoult’s law at a specific compostion. For example Chloroform – acetone mixture.
Or
(i)
.
(ii) Osmotic Pressure : The minimum excess pressure that has to be applied
on the solution to prevent the passage of solvent
molecules into it through semipermeable membrane is called osmotic pressure.
The osmotic pressure method has the advantage over other methods because
(i) osmotic pressure can be measured at room temperature and the molarity of the
solution is used instead of molality.
(ii) its magnitude is large as compared to other colligative properties even for very
dilute solutions.
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
BLUE PRINT 04
CLASS -XII
MAXIMUM MARKS:70
UNIT
NO.
CHAPTER
MCQ
1
Mark
each
SUBJECT- CHEMISTRY (043)
TIME: 3HRS
A/R
1
Mark
each
Section -A
1
2
3
Solutions
Electro Chemistry
Chemical Kinetics
4
d and f block
elements
5
6
7
8
9
10
Coordination
compounds
Haloalkanes and
Haloarenes
Alcohols Phenols
and Ethers
Aldehydes,
Ketones and
Carboxylic acids
Amines
Biomolecules
VSA
SA
CASE-BASED
LONG ANS TYPE
2 Marks each
with internal
choice in one
question
3 Marks each with
internal choice in one
question like attempt any
two out of three parts
4 marks each (1+1+2).
No MCQ, internal
choice in one
question in a sub part
of two marks
5 Marks each with
internal choice in two
questions and one
question has the
choice like attempt
any five parts out of
given 7 parts
Section -B
Section -C
Section -D
Section-E
1(3)
1(3)
1(4)
1(2)
1(1)
2(1)
1(1)
1(1)
1(2)
1(5) with choice
1(4) With internal
choice in two marks
question
2(1)
1(1)
2(1)
2(1)
1(1)
1(1)
12(12)
4(11)
1(3)
1(3)
3(6)
1(3) Attempt any two out
of three parts
4(6)
1(2) With
internal
choice
1(3)
5(8)
1(2)
5(10)
1(3)
7(21)
1(1)
1(5) With choice
4(4)
2(7)
4(9)
5(8)
1(3)
1(2)
1(1)
1(5) attempt any five
out of seven parts
TOTAL
MARKS
2(8)
3(15)
2(6)
3(6)
33(70)
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
SAMPLE PAPER - 04
CHEMISTRY THEORY (043)
CLASS - XII
Max. Marks:70
Time: 3 hours
General Instructions:
Read the following instructions carefully.
(a) There are 33 questions in this question paper with internal choice.
(b) SECTION A consists of 16 multiple -choice questions carrying 1 mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7 short answer questions carrying 3 marks each.
(e) SECTION D consists of 2 case - based questions carrying 4 marks each.
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory.
(h) Use of log tables and calculators is not allowed.
Q.
QUESTION
M
Section A
1.
The amount of electricity required to produce one mole of Zn from ZnSO4 solution will be:
(a) 3F
2.
(b) 2F
(d) 4F
If the rate of a gaseous reaction is independent of pressure, the order of reaction is:
(a) 0
3.
(c) 1F
(b) 1
(c) 2
1
1
(d) 3
For a chemical reaction A→B, it is found that the rate of reaction doubles when the
1
concentration of A is increased four times. The order of reaction is
(a) Two
4.
(b) One
(c) Half
(d) Zero
The magnetic nature of elements depend on the presence of unpaired electrons. Identify the
1
configuration of transition element, which shows highest magnetic moment.
(a) 3d7
5.
(b) 3d5
(c) 3d8
(d) 3d2
Electronic configuration of a transition element X in +3 oxidation state is [Ar] 3d5. What is its
atomic number?
(a) 25
(b) 26
1
(c) 27
(d) 24
6.
Chlorobenzene reacts with Cl2 in the presence of FeCl3 giving ortho and para chloro
1
compounds. The reaction is:
7.
(a) Nucleophilic substitution
(b) Nucleophilic addition
(c) Electrophilic addition
(d) Electrophilic substitution
Aldehydes other than formaldehyde react with Grignard’s reagent to give addition products
1
which on hydrolysis give
8.
9.
10
(a) tertiary alcohols
(b) secondary alcohols
(c) primary alcohols
(d) carboxylic acids
In the following compounds: The order of acidity is
(a) III > IV > I > II
(b) I > IV > III > II
(c) II > I > III > IV
(d) IV > III > I > II
Methyl ketones are usually characterised through
(b) Iodoform test
(c) Schiff’stest
(d) Benedict solution test
Imine derivatives of aldehyde and ketone is called as
(b) Fehling’s reagent
1
(c) Schiff’s base
(d) Schiff’s acid.
Amine that cannot be prepared by Gabricl-Phthalmidie synthesis is
(a) aniline
12.
1
(a) Tollen’s reagent
(a) Schiff’s reagent
11.
1
(b) benzyl amine
(c) methyl amine
1
(d) iso-butylamine
Which of the following Amino acid is optically inactive?
(a) Glycine
(b) Valine
(c) Alanine
(d) Phenyl alanine
For the Questions from Q No 13 to 16, select the most appropriate answer from the options
given below:
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
1
13.
Assertion (A): For complex reaction, the order of overall reaction is equal to the molecularity of 1
the slowest step of the reaction.
Reason (R): The overall rate of the complex reaction is controlled by the slowest step of the
reaction
14.
Assertion -Compounds containing —CHO group are easily oxidised to corresponding
1
carboxylic acids.
Reason: Carboxylic acids can be reduced to alcohols by treatment with LiAlH4
15.
Assertion: Ethers behave as bases in the presence of mineral acids.
1
Reason: Due to the presence of lone pairs of electrons on oxygen.
16.
Assertion: Conductivity of an electrolyte increases with decrease in concentration.
1
Reason: Number of ions per unit volume decreases on dilution.
SECTION B
17.
Explain why:
2
(a) The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.
(b) Alkyl halides, though polar, are immiscible with water
18.
A reaction is first order with respect to A & second order with respect to B
2
(i)How is the rate affected on increasing Concentration of B three times.
(ii)How is the rate affected when concentration of A is reduced to half & that of B is doubled.
19.
(i) Mention the condition when Raoult’s law becomes special case of Henry’s law
2
(ii) At the same temperature, H2 is more soluble in water than He, which of them will have
higher KH value and why?
20.
Explain the following
2
(i) Cl-CH2COOH has lower Pka than CH3COOH.
(ii) There are two –NH2 groups in semicarbazide, only one is involved in the formation of
semicabazone
OR
(ii) Illustrate the following name reactions giving a chemical equation in each case(i) HVZ reaction (ii) Clemmensen’s reduction
21.
Differentiate between
2
(i) Nucleotides and nucleosides (ii) Peptide and glycosidic linkage
22.
Calculate e.m.f. of the following cell at 298 K :
3
2Cr(s) + 3Fe2+ (0.1M) → 2Cr3+ (0.01M) + 3Fe(s)
E°(Cr3+ | Cr) = – 0.74 E° (Fe2+ | Fe) = – 0.44 V
23.
The half-life for radioactive decay of C-14 isotope is 5730 years. An archaeological artefact
3
containing wood had only 80% of the C-14 found in a living tree. Estimate the age of the
sample. ( log 2= 0.3010)
24.
a) Explain on the basis of valence bond theory that [Ni(CN)4] 2- ion with square planar structure
3
is diamagnetic and [NiCl4] 2- ion with tetrahedral geometry is paramagnetic.
b) FeSO4 solution mixed with (NH4)2SO4 solution in 1: 1 molar ratio gives the test of Fe2+ ion
but CuSO4 solution mixed with aqueous ammonia in 1:4 molar ratio does not give the test of
Cu2+ ion. Explain why?
25.
(a) Which one of the following compounds will undergo faster hydrolysis reaction by SN1
3
mechanism? Justify your answer. C6H5CH2Cl or CH3CH2CH2Cl
(b) What happens when chlorobenzene reacts with Sodium hydroxide at 623K and 300 atm
pressure?
26.
Give equations of the following reactions:
3
(i) Oxidation of propan-1-ol with alkaline KMnO4 solution.
(ii) Conc. HNO3 with phenol.
(iii) Treating phenol with chloroform in the presence of aqueous NaOH.
27.
Do any two parts
3
(i) Arrange the following in the increasing order of their reactivity towards nucleophillic
reaction C6H5COCH3 ,CH3CHO, CH3COCH3
(ii) How will you distinguish between acetophenone and benzophenone (iii) Complete the
following
28.
(a) Name the products of hydrolysis of lactose
3
(b) Write down the structures and names of the products formed when D-glucose is treated with
(i) Hydroxylamine (ii) Acetic anhydride
In Question no 29 & 30 read the paragraph and answer the question given at the end of
paragraph.
29.
A device used to convert the energy evolved in a redox reaction into electrical energy is called
an electrochemical cell. These devices are also called galvanic cells or voltaic cells, after the
names of Luigi Galvani (1780) and Alessandro Volta (1800) who were the first to perform
experiments on the conversion of chemical energy into electrical energy. How exactly the
chemical energy of a redox reaction is converted into electrical energy can be seen from the
following example: Redox reaction between Zn and CuSO4. The reaction is represented as:
Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). It may also be written in ionic form as: Zn + Cu2+
4
→ Zn2+ + Cu. The reaction essentially comprises of two half reactions: one for reduction and
the other for oxidation. Zn(s) → Zn2+(aq) + 2e- ;Cu2+(aq) + 2e- → Cu(s) Thus, Zn is oxidized
to Zn2+ in the oxidation half reaction and Cu2+ is reduced to Cu in the reduction half reaction.
The overall reaction can be obtained by adding the two half reactions. ᴧ0m NaCl = 126.4
Scm2mol-1 HCl = 426.1 S.cm2mol-1 CH3COONa(ᴧ0m) = 91.5 Scm2mol-1 NH4Cl(ᴧ0m) = 129.8
Scm2mol-1
Electrochemical cell based on redox reaction
(a) What is the direction of flow of current in a cell?
(b) In the above electrochemical cell which one acts as anode and which acts as cathode.
(c) (i)The equilibrium can be achieved in chemical reaction at what value of e.m.f ?
(ii) Why an electrochemical cell stops working after sometime?
Or
(c )Write two functions of salt bridge?
30.
The d-block, which lies between s and p-blocks contains, elements of groups 3-12, in which d-
4
orbitals are progressively filled in each of four long periods of periodic table. These elements
are also called transition elements or metals. The elements constituting the f-block are those in
which 4f and 5f-orbitals are progressively filled. They are place in a separate panel at the
bottom of the periodic table. The elements of f-block are also called inner-transition.
(i) Which group elements are called Transition elements?
(ii) Write the general outermost configuration of f-block elements..
(iii) Why the paramagnetic characteristic in 3d- transition series increases up to Cr and then
decreases?
Or
Out of La(OH)3 and Lu(OH)3 , which is more basic and why?
31
(a) Explain why on addition of 1 mol glucose or NaCl to 1 litre water, the boiling point of water
5
increases while on addition of 1 mol of methyl alcohol to 1 litre of water decreases its boiling
point?
(b) Calculate the amount of CaCl2(molar mass=111g/mol) which must be added to 500g of
water to lower its freezing point by 2K, assuming CaCl2 is completely dissociated.(Kf for
water=1.86 Kkgmol-1 )
OR
(a) Why does measurement of osmotic pressure method is preferred for the determination of
molar masses of macromolecules such as proteins and polymers?
(b) Calculate the value of van’t Hoff factor ‘i’ for an aqueous solution of AlCl3 which is
0.01molal.(Given : Kf for water = 1.86 K kg mol-1 , Tf of solution = -0.068 0C
32
Attempt any five:
5
(a) (i) Which transition element in 3d series has maximum number of unpaired electrons
(ii) Name a member of lanthanoid series which is well known to exhibit +4 oxidation state and
why?
(b) The highest oxidation state is exhibited in oxoanions of transition metals.
(c) HCl is not used to acidify KMnO4 solution.
(d) Transition metals have high enthalpy of atomisation.
(e) Eo (M2+/M) value for Cu is +0.34V while that of Zn is -0.76 V
(f) Chromium is typically hard metal while mercury is a liquid .
(g) Complete and balance the following equation
33
:
Cr2O7 2-+ Fe2+ + H+→
(a) An aromatic compound 'A' on treatment with aqueous ammonia and heating, forms
compound 'B' which on heating with Br2 and KOH forms a compound 'C' of molecular formula
C6H7N. Write the structures and IUPAC names of compound A, B and C
(b) Arrange the following: (i) In decreasing order of the pKb values:
C2H5NH2 , C6H5NHCH3 , (C2H5 )2NH and C6H5NH2
(ii) In increasing order of basic strength:
Aniline, p-nitroaniline and p-toluidine
OR
Complete the following reactions:
(i) C6H5N2Cl + H3PO2 + H2O →
(ii) C6H5NH2 + CH3COCl →
(iii) C2H5NH2 + C6H5SO2Cl →
(iv) C2H5NH2 + HNO2 →
(v) CH3CH2NH2 + CHCl3 + KOH (Alcoholic) →
5
KENDRIYA VIDYALAYA SANGATHAN
(IN-SERVICE COURSE 2023-24, AHMEDABAD REGION)
CLASS XII- SESSION ENDING EXAMINATION (SEE)
SAMPLE PAPER - 04
CHEMISTRY THEORY (043)
Marking Scheme
Q.
No
Correct option
MARKS
1
B
1
2
A
1
3
C
1
4
B
1
5
B
1
6
D
1
7
D
1
8
D
1
9
B
1
10
C
1
11
A
1
12
A
1
13
A
1
14
B
1
15
A
1
16
D
1
17
2
carbon of
cyclohexyl chloride
29
a) The current flows from cathode to anode
b) Zn rod acts as anode and Cu rod acts as cathode
c) At Zero emf, the cell reaction attains equilibrium
4
c)
30
a)
b)
c)
The electrochemical cell stops working after some time
because the electrode potential of both electrodes become
equal.
OR
Two functions of salt bridge are:
I. It maintains electrical neutrality in both compartments
II.It completes the circuit.
Elements from group 3 – 11 are called transition elements.
(n-2) f1-14 (n-1)d0-1 ns2
Because upto Cr the number of unpaired electrons increases
and then decreases.
OR
Size of lanthanoid ion decreases from La3+ to Lu3+, tendency
to give hydroxyl ion decreases so basic strength decreases.
4
KENDRIYA VIDYALAYA SANGTHAN
IN-SERVICE COURSE 2023-24, AHMEDABAD REGION
CLASS XII SESSION ENDING EXAMINATION(BOARD)
CHEMISTRY THEORY (043)
SAMPLE PAPER-05
BLUE PRINT
S.NO.
Name of Unit
Objective type Very short
Short answer
Questions (1) answer question Question (3)
(2)
1
Solutions
2
Electrochemistry
2(1)
3
Chemical Kinetics
2(1)
4
d- and f- Block Elements
2(1)
5
Co-ordination Compounds
6
Haloalkanes and Haloarenes
1(1)
7
Alcohols, Phenols and Ethers
3(1)
8
Aldehydes, Ketones and
carboxylic acids
3(1)
9
Amines
1(1)
10
Biomolecules
2(1)
1(2)
1(3)
TOTAL
16(1)
5(2)
7(3)
Case based
Question (4)
1(2)
1(5)
1(3)
1(2)
Long answer
Questions (5)
1(4)
7
1(5)
1(2)
1(2)
7
9
1(3)
1(3)
Total
marks
1(4)
7
7
1(3)
6
1(3)
6
1(3)
8
1(5)
6
7
2(4)
3(5)
70
KENDRIYA VIDYALAYA SANGTHAN
IN-SERVICE COURSE 2023-24, AHMEDABAD REGION
CLASS XII SESSION ENDING EXAMINATION(BOARD)
CHEMISTRY THEORY (043)
GROUP -6
SAMPLE PAPER-5
Class- XII
Subject- Chemistry (043)
Time: 3 Hours
General Instructions:
Read the following instructions carefully.
a) There are 33 questions in this question paper with internal choice.
MM: 70
b) SECTION A consists of 16 multiple-choice questions carrying 1 mark each.
c) SECTION B consists of 5 very short answer questions carrying 2 marks each.
d) SECTION C consists of 7 short answer questions carrying 3 marks each.
e) SECTION D consists of 2 case- based questions carrying 4 marks each.
f) SECTION E consists of 3 long answer questions carrying 5 marks each.
g) All questions are compulsory.
h) Use of log tables and calculators is not allowed
SECTION -A
The following questions are multiple-choice questions with one correct answer. Each
carries 1 mark. There is no internal choice in this section.
1
On electrolysis of dilute sulphuric acid using platinum electrode, the product
obtained at anode will be?
(a)Hydrogen
(b)Sulphur dioxide
(c)Hydrogen sulphide
(d)Oxygen
2
Pyrimidine base present in RNA is(a)Uracil
(b)Thymine
(c)Cytosine
(d)Guanine
3
Which of the following alcohol reacts fastest with conc. HCl and anhydrous
ZnCl2 is
(a)butanol-1
(b)Butanol-2
(c)2-Methylbutanol-1
(d)2-Methylpentanol-2
4
How much coulomb/ charge is required for the reduction of one mol MnO4 - into
Mn 2+ ?
(a)96500 C
(b)289500 C
(c)482500 C
(d)868500 C
5
Compounds of transition metals are coloured due to(a)their similar atomic size
(b)their incomplete (n-1) d orbital
(c)their reducing property
(d)their variable oxidation state
question
1
1
1
1
1
6
7
8
9
10
11
12
13
14
15
The synthesis of alkyl iodide is best accomplished by(a)Finkelstein reaction
(b)Swarts reaction
(c)Balz-Schiemann reaction
(d)Sandmeyer’s reaction
Which of the following cannot be made by using Willamson synthesis?
(a)Methoxy benzene
(b)tert.- butylmethyl ether
(c)Di-tert-butylether
(d)Methyl ethyl ether
When a catalyst increases the rate of a chemical reaction, the rate constant
(a) remains constant
(b) increases
(c) decreases
(d) may increase or decrease
Which of the following disaccharide gives two aldose molecules on hydrolysis?
(a)Maltose
(b)Sucrose
(c)Lactose
(d)All of these
The reagent used for differentiation of acetaldehyde and acetophenone is
(a)NaHSO 3
(b)NH 2OH
(c) I2 and NaOH
(d)C6 H5 NHNH 2
Which of the following is more acidic?
(a)Benzoic acid
(b)p-Nitrobenzoic acid
(c)Ethanoic acid
(d)4-Methoxy benzoic acid
Which of the following gives yellow precipitate of Iodoform on adding
Iodine and aq. NaOH?
(a)Methanol
(b)2-Methylpropan-2-ol
(c)Propanol-2
(d)Butanol-1
Given below are two statements labelled as Assertion (A) and Reason (R)
ASSERTION: Order of reaction can be fractional but molecularity is never be
fractional.
REASON: Order of reaction does not depend upon the stoichiometric
coefficients of the balanced equation.
Select the most appropriate answer from the options given below:
a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
1
Given below are two statements labelled as Assertion (A) and Reason (R)
ASSERTION: Mn atom loses ns electrons first during ionization as
compared to (n-1) d electrons.
REASON: The effective nuclear charge experienced by (n-1) d electron
is greater than that by ns electrons.
Select the most appropriate answer from the options given below:
a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
Given below are two statements labelled as Assertion (A) and Reason (R)
ASSERTION- Both aliphatic and aromatic 1o amine give carbylamine test.
REASON- In carbylamine reaction, a mixture of 1o amine and carbon
tetrachloride is heated in presence of alcoholic KOH.
Select the most appropriate answer from the options given below:
a. Both A and R are true and R is the correct explanation of A
1
1
1
1
1
1
1
1
1
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
16 Given below are two statements labelled as Assertion (A) and Reason (R)
ASSERTION- Ketones can easily give nucleophilic addition reaction than
aldehydes.
REASON: Ketones have more steric hinderance on -CO- group.
Select the most appropriate answer from the options given below:
a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
SECTION -B
This section contains 5 questions with internal choice in one question. The following
Questions are very short answer type and carry 2 marks each.
17 A solution of urea in water has a boiling point of 100.128 0 C. Calculate the
freezing point of the same solution. (K f and K b are 1.86 and 0.52 K/m)
18 A chemical reaction, 2X → 4Y + Z, in gas phase occurs in closed vessel. The
concentration of Y is found to be increased by 5 x 10 -3 mol /L in 10 minutes.
Calculate the rate of disappearance of X.
19 (a)Name the products obtained on hydrolysis of nucleotide having uracil.
(b)Which structure remains intact during denaturation of protein?
20 (a) Write the IUPAC name of DDT.
(b)Arrange the following in increasing order of reactivity towards SN 1 reaction
1-Chlorobutane, 1-Chloro-2,2-dimethylpropane,
1-Chloro-2-methylbutane, 1-Chloro-3-methylbutane
21 Give reason why(a)Palladium is poisoned with BaSO4 during the formation of aldehyde from
acid chloride?
(b)Arrange the following in increasing order of reactivityAcetophenone, Benzaldehyde, Benzophenone
OR
(i)How can you convert ethanal into butan-2-ol. Write equation.
(ii)What happens when calcium ethanoate is dry distilled? Write equation.
1
2
2
2
2
2
SECTION-C
This section contains 7 questions with internal choice in one question. The following
questions are short answer type and carry 3 marks each.
22 (a)A coordination compound with molecular formula CrCl 3.5H2O
3
precipitate one moles of AgCl with AgNO3 solution. Write its structural
formula.
(b) Arrange the following in correct order of absorption of wavelength
of light in the visible region.
[Ni(NH3)6]2+ , [Ni(en)3]2+ , [Ni(H2O)6]2+
(c)Draw the labelled crystal field splitting diagram for an octahedral
complex having d6 electrons if Δ 0 < P.
23 (a) Which carbon atom have different configuration in anomers of glucose?
3
(b) What is the difference between two types of secondary structure of
protein?
24
25
26
27
(c)Write the equation of glucose with bromine water.
(a)Calculate the Λ m o of Al2 (SO 4) 3 if the molar conductivities at infinite
dilution of AlCl3, HCl and H2 SO 4 are 130, 426 and 860 S cm 2 mol -1
respectively.
3
(b)Write the expression of Nernst equation for the following cellAl (s) l Al 3+ (0.01 M ) ll Fe 2+ (0.1 M) l Fe (s)
An organic compound ‘A’ (Molecular formula C8H8O) gives positive 2,4-DNP 3
test. It gives yellow precipitate of compound ‘B’ on treatment with iodine and
sodium hydroxide solution. Compound ‘A’ does not give Tollen’s or Fehling’s
test. On drastic oxidation with KMnO4 it forms carboxylic acid ‘B’ (Molecular
formula C7H6O2) which is also formed along with the yellow compound in the
above reaction. Identify A and B(Name and formula) and also write the reaction
of compound ‘A’ with 2,4-DNP.
(a)Why Chlorobenzene is less reactive than Chloromethane towards
3
nucleophilic substitution reaction.
(b)Para isomer of dihalobenzene have high melting point than ortho and
meta isomers.
(c)Which of the following is optically active compound?
1,1,2,2-tetrachlorobutane, 1-Chlorobutane, 2-Chloropropane
3-Chloropentane, 2- Chloropentane
The following data were obtained during the first order thermal decomposition of
SO2 Cl 2 at constant volume. Calculate the rate constant.
SO2 Cl 2 (g) → SO2 (g) + Cl 2 (g)
3
Experiment Time(sec)
Total pressure(atm.)
1
0
0.4
2
100
0.7
28 Answer any three of the following questions3
(a)Whose boiling point is less among o-nitrophenol and p-nitrophenol
and why?
(b)Name a compound used to prepare aspirin.
(c)Write equation for Kolbe’s reaction.
(d)What is the major product (Formula and name) when tert.butylbromide
react with sodium methoxide? Write the nature of reaction also.
SECTION-D
The following questions are case-based questions. Each question has an internal choice and
carries 4(1+1+2) marks each. Read the passage carefully and answer the questions that
follow.
29 Read the following passage4
An electrochemical cell is a device that can generate electrical energy from the
chemical reactions occurring in it, or use the electrical energy supplied to it to
facilitate chemical reactions in it. These devices are capable of converting
chemical energy into electrical energy, or vice versa. Electro chemical cell is
constructed by two half cells connected through salt bridge A common example
of an electrochemical cell is a standard 1.5-volt cell which is used to power many
electrical appliances such as TV remotes and clocks.
Such cells capable of generating an electric current from the chemical reactions
occurring in them care called Galvanic cells or Voltaic cells. Alternatively, the
cells which cause chemical reactions to occur in them when an electric current is
passed through them are called electrolytic cells.
30
31
32
Answer the following questions:
(a)Name a cell which is use for electroplating
OR
Name a cell which is used in TV Remote.
(b) Write the condition to convert electrochemical cell into electrolytic cell?
Is it spontaneous or nonspontaneous?
(c) Name the component used to connect two half cell and also write its two
applications.
Read the following passageThe coordination compounds are of great importance. These compounds are are
widely present in the minerals, plants and animal worlds and are known to play
many important functions in the area of analytical chemistry, metallurgy,
biological system, industry and medicine. Formation of coordination compound
is largely used in analytical chemistry for the qualitative detection and
quantitative estimations of metal ions. Coordination compounds also find in
several important applications in the field of medicines. Several coordination
compounds are also used as antidote to poisoning caused by the ingestion of
poisonous metals by human beings. variety of sectors. Coordination complexes
are also used as catalyst in technological process during organic synthesis. They
are also used in medicines, dyes and pigments etc.
Answer the following questions(i)Name the ligand used to detect the hardness of water. What is the nature of
this ligand?
(ii)Name a metal which can be extracted by complex formation.
(iii)Name a deficiency disease caused by Vitamin B 12 and coordination
compound of which metal is used for its treatment?
OR
Name IUPAC name of a coordination compound and the isomerism shown
by it which is used for the treatment of cancer therapy.
SECTION-E
Answer any five of the following questions(a)Why pKb value of aniline is more than ethylamine.
(b)Why meta product is formed along with ortho and para product during
direct nitration of aniline?
(c)Write an equation for the formation of azo dye. ( write equation)
(d) How can you convert Benzoic acid into aniline?
(e) Arrange the following in increasing order of boiling point.
C2H5OH,(CH3)2 NH, C2H5NH2
(f) Can aniline be prepared by Gabriel phthalimide reaction? Give reason in
favour of your statement.
(g)Why N,N-diethylbenzenesulphonamide is insoluble in alkali?
Answer the following questions:
(a)Calculate the ‘spin only’ magnetic moment of a divalent ion of a metal M
4
5
5
33
in aqueous solution. The atomic number of the metal M is 28.
(b) How does acidified potassium permanganate solution react with oxalate
ions? Write balanced ionic equation.
(c) Write an alloy of lanthanoid along with its composition.
(d) Out of [Sc (H2O) 6] 3+ and [Ti (H2O) 6] 3+ ions which one is coloured and
Why?
(e) Name an element of 3d series having maximum oxidation state.
OR
(i) Why actinoids shows large number of oxidation state than lanthanoides?
(ii) Which is a stronger reducing agent Cr 2+ or Fe 2+ and why?
(iii) How does acidified potassium dichromate solution react with iodide
ions? Write balanced ionic equation.
(iv)Write a disproportionation reaction shown by a transition element.
(v)Why is it difficult to separate Nb and Ta?
(a) The average osmotic pressure of human blood is 7.7 atm at 40 0 C.
Assuming the concentration to be essentially the same as the molality,
find the freezing point of blood (K f for water=1.86 K/m)
(b)What type of deviation from Raoult’s is shown by maximum boiling
azeotropes? Give one example and draw the graph.
OR
(i) The vapour pressure of pure benzene at a certain temperature is 0.850 bar. A
non-volatile, non-electrolyte solid weighing 0.5 g is added to 39.0 g of benzene
(molar mass 78 g/mol). The vapour pressure of the solution then is 0.845 bar.
What is the molar mass of the solid substance?
(ii)What happens when RBC is placed in 1.5% aqueous solution of NaCl?
(iii)Why raw mangoes shrink into pickle when placed in concentrated
solution of common salt?
5
KENDRIYA VIDYALAYA SANGTHAN
IN-SERVICE COURSE 2023-24, AHMEDABAD REGION
CLASS XII SESSION ENDING EXAMINATION(BOARD)
CHEMISTRY THEORY (043)
GROUP 6
SAMPLE PAPER-5
XII CHEMISTRY (043)
MARKING SCHEME
Q.NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Expected Answer
d
a
d
c
b
a
c
b
a
a
b
c
a
a
c
d
ΔT b = Kb x m
ΔTf Kf x m
0.128 = 0.52
ΔTf
1.86
Δ T f = 0.128 x 1.86 = 0.457
0.52
Freezing point of solution = 0 o – 0.457 = - 0.457 o C
Rate of appearance of Y = Δ[Y] = 5 x 10 -3 = 5 x 10 -4 Mol L -1 min -1
Δt
10
Rate of disappearance of X = - Δ [X] = 2Δ [Y] = 2.5 x10 -4 mol L -1 min -1
Δt
4 Δt
(a)Ribose sugar, Uracil, Phosphoric acid
(b)Primary structure
(a) 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane
(b) 1- Chloroobutane <1-Chloro-3-methylbutane < 1- Chloro-2-methylbutane
< 1-Chloro-2,2-dimethylpropane
(a)To control reduction and get only aldehyde and prevent the further
formation of alcohol
(b)Benzophenone< acetophenone < Benzaldehyde
Marks
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
½
½
½
1/2
1
1
1
1
1
1
1
1
22
23
24
25
OR
(i)CH3 CHO + C2 H5 MgBr → CH3 CH(C2 H5)OMgBr +HOH
↓
CH3 CH(OH) C2 H5
(ii) (CH3 COO) 2 Ca (dry distillation) -------→ CH3 CO CH3 + CaCO 3
(a)[Cr (H2O) 4 Cl2] Cl. H2 O
(b) [Ni(H2O)6]2+ < [Ni(NH3)6]2+ <[Ni(en)3]2+
1
1
1
1
(c)
1
(a)C-1
(b)α – helix structure – intramolecular hydrogen bond
Β- pleated sheet structure – intermolecular hydrogen bond
(c) CHO-(CHOH)4 - CH2OH + Br 2 → OHC- (CHOH4 - COOH
Gluconic acid
o
o
o
(a)Λ m Al2 (SO4) 3 = 2(Λ m AlCl3 ) + 3(Λ m H2 SO 4 )- 6(Λ m o HCl)
Λ m o Al2 (SO4) 3 = 2x 130 + 3 x 860 – 6 x 426
Λ m o Al2 (SO4) 3 = 260 + 2580 – 2556 = 284 S cm 2 mol -1
(b)E cell = E o cell – 2.303RT log [Al 3+] 2
nF
[Fe 2+ ] 3
A= acetophenone, C6 H5 COCH 3
B = Benzoic acid, C6 H5 COOH
1
1
1
½
½
1
1
½+1/2
½+1/2
1
26
27
(a)Chlorobenzene is less reactive toward nucleophilic substitution due to
shorter bond length of C – X bond and sp 2 hybridisation of Carbon atom
(b)Para isomer of dihalobenzene have high boiling point due to symmetrical
shape
(c) 2- Chloropentane
SO2 Cl 2 (g) → SO2 (g) + Cl 2 (g)
1
1
1
28
Initial pressure
Po
0
0
o
Pressure at time t
(P –P)
P
P
At 100 sec
Total pressure = ( P o – P ) + P + P
0.7 = 0.4 + P
P = 0.3
o
o
K = 2.303/t log P / P - P
K = 2.303 /100 log 0.4 / 0.1
K = 1.386 x 10 -2 sec -1
Any Three
(a)Boiling point of o- nitrophenol is less due to intramolecular hydrogen
bonding
(b)Salicyalic acid or 2- Hydroxy benzoic acid
(c)
½
½
½
½
½
1/2
1
1
1
(d)
½
29
30
31
Elimination reaction
(a) electrolytic cell
OR
Dry cell
(b)Eext > E cell (or External potential applied is more than cell potential)
Nonspontaneous
(c)Salt bridge
(i) It is used to connect two half cells
(ii) It prevents the intermixing of electrolytes of two half cells
(iii) It allows the migration of some selected ions
(any two)
(i)EDTA, Nature- Polydentate ligand or negative ligand
(ii)Ag or Au
(iii)Pernicious anaemia , Coordination compound of Co with
cyanocobalamine
OR
Cis- diamminedichloridoplatinum(II) , Geometrical isomerism
Any Five
(a)pKb value of aniline is more than ethylamine because ethylamine is more
basic due to presence of ethyl group which shows + I effect and aniline is less
basic due to presence of phenyl group which shows - I effect.
(b)Direct nitration of aniline form anilinium ion which is meta directing.
(c) Any one of the following
1/2
1
1
½
½
1
½,1/2
½+1/2
1
1+1
1+1
1
1
1
1
1
32
33
(d) C6H5 COOH + NH3 → C6H5 CO NH2
C6H5 CO NH2 +Br 2 + 4KOH→ C6H5NH2 + 2KBr + K2 CO3
(e) (CH3) 2 NH < C2 H5 NH 2 < C2 H5 OH
(f)Aniline cannot be prepared by Gabriel phthalimide reaction because aryl
halide do not undergo nucleophilic substitution reaction.
(g) Because N,N-diethylbenzenesulphonamide does not contain any
hydrogen atom attached to N atom, so it is not acidic and insoluble in alkali.
(a)M 2+ =[Ar]. 3d8, No. of unpaired electrons = 2
Magnetic moment= √n(n+2) = √8 BM= 2.82 BM
(b) 2MnO 4 - + 5 C2O4 2- + 16 H + → 2 Mn 2+ + 10 CO 2 + 8 H2O
(c) Misch metall, It contains 95 % lanthanoid 5% Fe and trace of C, S, Ca
and Al
(d) [Ti (H2O) 6] 3+ is coloured due to d-d transition /have one unpaired
electron
(e)Mn
OR
(i) Actinoides shows large number of oxidation state due to very small energy
gap between 5f, 6d and 7s.
(ii) Cr 2+ is stronger reducing agent than Fe 2+ because E 0 Cr 3+/ Cr 2+ value
is -ve while E 0 Fe 3+/ Fe 2+ is +ve
(iii) Cr2 O7 2- + 6 I - + 14 H + → 2 Cr 3+ + 3I 2 + 7 H2O
+6
+7
+4
2+
(iv) 3 MnO 4 + 4 H → 2 MnO 4 + MnO 2 + 2 H2O
(v)Nb and Ta have same atomic radii due to lanthanoides contraction
(a) π= CRT
C = π / RT
C = 7.7 / 0.0831b x 313 = 0.296
ΔT f = k f m
ΔT f = 1.86 x 0.296 = 0.55
Freezing point = 0 o - 0.55 = - 0.55 o C
(b)Negative deviation,
Ex. Acetone and chloroform (or any other correct answer)
1
1
1
1
1
1
1
1
1
1
1
1
1/2
½
½
1
½
1/2
½
1
o
(i ) P – P = n = w/m
P o N W/M
0.850- 0.845 = 0.5 / m
0.850
39/ 78
M = 170 g/mol
(ii)RBC shrink
(iii) due to osmosis
OR
1
1
1
1
1
SAMPLE PAPER-6
CHEMISTRY XII
BLUE PRINT
S.NO.
Name of Unit
Objective
type
Questions
(1)
Very short
answer
question
(2)
1
Solutions
2
Electrochemistry
2(1)
3
Chemical Kinetics
2(1)
4
d- and f- Block Elements
2(1)
5
Co-ordination Compounds
6
Haloalkanes and Haloarenes
1(1)
7
Alcohols, Phenols and Ethers
3(1)
8
Aldehydes, Ketones and
carboxylic acids
3(1)
9
Amines
1(1)
10
Biomolecules
2(1)
1(2)
1(3)
TOTAL
16(1)
5(2)
7(3)
2(2)
Short
answer
Question
(3)
Case based
Question
(4)
Long
answer
Questions
(5)
1(3)
1(3)
7
1(4)
9
1(5)
1(5)
1(3)
1(2)
1(4)
7
7
7
1(3)
6
1(3)
6
1(5)
1(2)
Total
marks
1(3)
8
6
7
2(4)
3(5)
70
KENDRIYA VIDYALAYA SANGTHAN
IN-SERVICE COURSE 2023-24, AHMEDABAD REGION
CLASS XII SESSION ENDING EXAMINATION(BOARD)
CHEMISTRY THEORY (043)
SAMPLE PAPER-6
CHEMISTRY THEORY (043)
Max. Marks:70
Time: 3 hours
General Instructions:
Read the following instructions carefully
(a) There are 33 questions in this question paper with internal choice
(b) SECTION A consists of 16 multiple -choice questions carrying 1 mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7 short answer questions carrying 3 marks each.
(e) SECTION D consists of 2 case - based questions carrying 4 marks each
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory
(h) Use of log tables and calculators is not allowed
SECTION A
The following questions are multiple -choice questions with one correct answer. Each
question carries 1 mark. There is no internal choice in this section.
1
. The cell constant of a conductivity cell _____________.
(a) changes with change of electrolyte.
(b) changes with change of concentration of electrolyte.
(c) changes with temperature of electrolyte.
(d) remains constant for a cell
−𝐸𝑎
2
According to Arrhenius equation rate constant k is equals to k= A 𝑒 𝑅𝑇 . which of the
following options represents the graph of ln k vs
3
For the reaction N2 + 3H2 →2NH3, the rate
rate
𝑑 [𝑁2]
- 𝑑𝑡 is
𝑑[𝑁𝐻3]
𝑑𝑡
1
1
𝟏
𝑻
= 2X 10 -4 mol-1l-1S-1. Therefore, the
1
4
5
a) 10 -4 mol-1l-1S-1
b) 10 4 mol-1l-1S-1
c) 10-2 S mol-1l-1
d) 10-4 S mol-1l-1
The radius of La3+ (At. No. of La = 57) is 1.06 A°. Which one of the following given
values will be closest to the radius of Lu3+.
(a) 1.40 Å
(b) 1.06 Å
(c) 0.85 Å
(d) 1.60 Å
If n is the number of unpaired electrons, the magnetic moment (in BM) of transition metal
ion is given by
a) 2√𝑛(𝑛 + 2)
b) 2√2𝑛(𝑛 + 1)
c) 2√2𝑛(𝑛 − 1)
d) None of these
6
7
8
1
1
1
Based On the graph above, find the element with a melting point lower than 2000K
a) Y
b) X
c) Z
d) None of the above
The correct order of acid strength of the following compounds is
(i) Phenol (ii) p-Cresol
(iii) m-Nitrophenol
(iv) p-Nitro phenol
a) iii > ii > i > iv
b) iv> iii > I > ii
c) ii > iv > I > iii
d) I > ii > iv > iii
Which of the following reactions will not result in the formation of carbon-carbon bond?
a) Reimer-Tiemann reaction
b) Friedal craft’s acylation
c)Wurtz reaction
d) Cannizaro reaction
1
1
9
10
11
12
13
14
15
1
The carboxylic acid that doesnot undergo HVZ reaction is
a) CH3COOH
b) (CH3)2CHCOOH
c) CH3CH2CH2COOH
d) (CH3)3CCOOH
In a set of reactions propionic yielded a compound (D)
What is the structure of (D)
(a) CH3 CH2 CH2 NH2
(b) CH3 CH2 CO NH2
(c) CH3CH2NH CH3
(d) CH3CH2NH2
Which of the following carbohydrate do not have a glycosidic linkage?
a) Sucrose
b) Amylose
c) Galactose
d) Maltose
Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion: Phenols give o- and p-nitrophenol on nitration with conc. HNO3 and H2SO4
mixture.
Reason: —OH group in phenol is o–, p– directing.
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion: Fuel cells are pollution free
Reason: Fuel cells use hydrogen like fuels along with oxygen gas for current production
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion: Even though there are two- NH2 groups in semi carbazide, only one reacts with
carbonyl compounds.
1
1
1
1
1
1
16
17
18
19
20
21
22
Reason: Semi carbazide has two -NH2 groups out of which one is in resonance with the
carbonyl group
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion: The bond between adenine and thymine is stronger than the bond between
cytosine and guanine
Reason: Cytosine and guanine have a triple hydrogen bond while adenine and thymine
have a double bond
Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
SECTION B
This section contains 5 questions with internal choice in one question. The following
questions are very short answer type and carry 2 marks each
a) Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one
of the two gases will have the lower value of KH (Henry’s constant) and why?
b) Out of 1 M glucose and 2 M glucose, which one has a higher boiling point and
why?
What is van’t Hoff factor? What types of values can it have if in forming the solution, the
solute molecules undergo (i) Dissociation? (ii) Association?
2
Account for the following
a) The C-Cl bond length in chlorobenzene is shorter than that in CH3Cl
b) Chloroform is stored in amber-coloured bottles.
a) Arrange the following in the decreasing order of their basic strength in aqueous
solutions: CH3NH2, (CH3)2 NH, (CH3)3N and NH3
b) Write the IUPAC name of the following compound:
CH3NHCH(CH3)2
a) What is the difference between native protein and denatured protein?
b) Write the name of the vitamin responsible for the coagulation of blood.
SECTION C
This section contains 7 questions with internal choice in one question. The following
questions are short answer type and carry 3 marks each
Explain the following
a) Sucrose is dextrorotatory, but the mixture obtained after hydrolysis is laevo rotatory.
b) Amino acids behave like salts rather than simple amines or carboxylic acids.
c) The presence of an aldehydic group in glucose molecule
1
2
2
2
2
2
23
100 mg of a protein is dissolved in enough water to make 10.0 mL of a solution. If this
solution has an osmotic pressure of 13.3 mm Hg at 25°C, what is the molar mass of
protein? (R = 0.0821 L atm mol-1 K-1 and 760 mm Hg = 1 atm
3
24
An organic compound A with the molecular formula (+)C 4H9Br undergoes hydrolysis to form
3
(
25
)C4H9OH. Give the structure of A and write the mechanism of the reaction.
a) Identify A and B in each of the following processes
1+1+1
b)Give the chemical tests to distinguish between the following pairs of compounds:
Methylamine and Dimethylamine
c) How are the following conversions carried out
Ethanoyl chloride to Ethanenitrile
26
27
28
a) State Faradays second law of electrolysis.
b) Calculate the cell potential, E cell, at 25 °C for the cell if the initial concentration of
Ni(NO3)2 is 0.100 molar and the initial concentration of AgNO3 is 1.00 molar.
[E0Ni2+/Ni = -0.25 V; E0Ag+/Ag = 0.80 V; log 10-1 = -1 ]
a) Give IUPAC name of ionization isomer of [Ni (NH3)3NO3]Cl.
b) Which of the following is more stable complex and why?
[Co(NH3)6]3+ and [Co(en)3]3+
c) What is an ambidentate ligand?
OR
For the complex [Fe(en)2Cl2], Cl, (en = ethylene diamine), identify
(i) the oxidation number of iron,
(ii) the hybrid orbitals and the shape of the complex,
(iii) the magnetic behaviour of the complex,
(iv) the number of geometrical isomers,
(v) whether there is an optical isomer also, and
(vi) name of the complex. (At. no. of Fe = 26)
3
An aromatic compound ‘A’ on treatment with CHCl3 and KOH gives two compounds, both of
which give same product ‘B’ when distilled with Zinc dust. Oxidation of ‘B’ gives ‘C’ with
molecular formula C7H6O2. Sodium salt of ‘C’ on heating with soda lime gives ‘D’ which may also
be obtained by distilling ‘A’ with Zinc dust. Identify ‘A’, ‘B’, ‘C’ and ‘D’.
3
SECTION D
The following questions are case -based questions. Each question has an internal choice
and carries 4 (1+1+2) marks each. Read the passage carefully and answer the questions
that follow.
3
3
29
4
Read the passage and find the answer
While taking a seminar Remya told that,
Khoulrauschs law states that molar conductivity of any electrolyte is equal to sum of the
molar conductivity of individual ions. For finding molar conductivity of any weak
electrolyte graphical method is not suitable and the same can be find out by molar
conductivity value of corresponding strong salts.
Weak electrolytes have lower molar conductivities and lower degree of dissociation
at higher concentrations. The graph plotted between molar conductivity and c1/2 (where c
is the concentration) is not a straight line for weak electrolytes. The molar conductivity of
weak electrolyte increases steeply at lower concentrations. Therefore, limiting molar
conductivity, ʎom cannot be obtained by extrapolation of molar conductivity to zero
concentration. Hence, we use the Kohlrausch law of independent migration of ions for the
determination of limiting molar conductivity, ʎom for weak electrolytes.
a) This is true that 𝛬mº for CH3COOH cannot be determined experimentally? Support this
statement
b) Suppose you are the teacher teaching about khoulrauschs law and one student asked a
question that why weak electrolytes have higher molar conductivities at lower
concentrations, write your answer
c) The 𝛬mº for sodium iodide, sodium acetate, and magnesium acetate solution are 12.69,
9.10 and 18.78 S cm2 mol-1, respectively, at 298 K. Calculate 𝛬mº for magnesium iodide.
OR
d) The resistance and conductivity of a cell containing 0.001 M KCl solution at 298 K are
1500 Ω and 1.46 X 10−4 S cm−1, respectively. What is the cell constant of the cell?
30
Read the passage given below and answer the following questions
Arrangement of ligands in the order of their ability to cause splitting (Δ) is called spectrochemical
series. Ligands which cause large splitting (large Δ) are called strong field ligands while those
which cause small splitting (small Δ)are called weak field ligands. When strong field ligands like
CN-approach metal atom/ion, the value of Δo is large, so that electrons are forced to get paired up
in lower energy t2g orbitals. Hence, a low spin complex is resulted from strong field ligand. When
weak field ligands like halogens approach the metal atom/ion. The value of Δo is small, so that
electrons enter high energy eg orbitals rather than pairing in low energy t2g orbitals.Hence, a high
spin complex is resulted from weak field ligands. Strong field ligands have a tendency to form
inner orbital complexes by forcing the electrons to pair up. Whereas weak field ligands have
tendency to form outer orbital complex because inner electrons generally do not pair up.For
getting colour the central atom in a complex must contain unpaired electrons.
4
a) In an octahedral complex the central atom is in d4 configuration state, it came to
know that the ligand is cyanide ion, comment on coloring state of complex
b) Cyanide usually gives inner orbit complex, what nature makes cyanide to give
inner orbit complex
c) While analysing complexess you will observe that Ti4+ forms colourless
complexess even with weak ligands,if this statement is correct then support it with
suitable value points.
OR
Write the correct relation between Δo and Δt, where Δo denotes crystal field
splitting in octahedral complexes and Δt denotes crystal field splitting in tetrahedral
c
SECTION E
31
32
The following questions are long answer type and carry 5 marks each. All questions
have an internal choice
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the
product is dissolved in water, a yellow solution of compound (B) is obtained. After
treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised
from the solution. When compound (C) is treated with KCI, orange crystals of compound
(D) crystallise out. Identify A to D and also explain the reactions.
OR
a) Give reason
i)
Transition metals have high melting points.
ii)
The highest oxidation state of a transition metal exhibited in its oxide or
fluoride only.
b) What is meant by ‘lanthanoid contraction’?
c) Complete the following chemical equations:
(i) MnO4-(aq) + S2O32- (aq) + H2O (1) →
(ii) Cr2O72- (aq) + Fe2+ (aq) + H+ (aq) →
a) A reaction is of first order in reactant A and of second order in reactant B. How is
the rate of this reaction affected when the concentrations of A as well as B are
doubled?
(1)
b) Distinguish between ‘rate expression’ and ‘rate constant’ of a reaction. (1)
c) The value of rate constant k of a reaction depends on temperature. From the values
of k at two different temperatures, the Arrhenius parameters Ea and A can be calculated.
The rate constants of a reaction at 1000K and 1060K are 0.01M-1S -1 and 0.10M-1S -1
respectively. Find the values of Ea and log A .
(3)
a) Draw the plot of t1/2
1
OR
Vs initial concentration [A0] for a first order Reaction.
5
5
b) Differentiate Order and molecularity of a reaction.( any two points).
2
c) The rate of a first order reaction is 0.04 molL-1s-1 after 10 mins and 0.03molL-1s-1
2
after 20 mins of initiation. What is the half life of the reaction?
33
Attempt any five of the following:
d) Convert ethanoic acid to 2-chloro ethanoic acid.
e) Identify the product obtained when sodium benzoate is distilled with sodalime.
f) Arrange the following in increasing order of reactivity towards nucleophilic addition
reaction. Benzaldehyde, benzophenone, p-tolualdehyde, acetophenone.
g) Give simple test to distinguish between acetophenone and benzophenone.
5
KENDRIYA VIDYALAYA SANGTHAN
IN-SERVICE COURSE 2023-24, AHMEDABAD REGION
CLASS XII SESSION ENDING EXAMINATION(BOARD)
CHEMISTRY THEORY (043)
SAMPLE PAPER-6
CHEMISTRY THEORY (043)
MARKING SCHEME
1
2
(d) remains constant for a cell
1
1
3
4
5
6
7
a) 10 -4 mol-1l-1S-1
(c) 0.85 Å
2
√𝑛(𝑛 + 2)
c) Z
b) iv> iii > I > ii
Electron withdrawing groups increases acid strength and electron releasing groups
decreases acidic strength
1
1
1
1
1
8
9
d) Cannizaro reaction
1
1
10
11
12
13
14
15
16
17
c) (CH3)3CCOOH
(d) CH3CH2NH2
c)Galactose
(d) A is false but R is true
b) Both A and R are true but R is not the correct explanation of A.
(a) Both A and R are true and R is the correct explanation of A
d) A is false but R is true
a) Gas (A) will have lower value of KH (Henry’s constant) than Gas (B at the same
temperature because lesser the solubility of a gas in a given solvent, higher will be
the value of KH for a gas.
p=KH x
b) 2M glucose will have a higher boiling point than 1M glucose because elevation in
boiling point is a colligative property which depends upon the number of particles in
the solution which is more in the case of 2M glucose solution
1
1
1
1
1
1
1
1
Van’t Hoff factor: It is defined as the ratio of the experimental value of the colligative
property to the calculated value of the colligative property.
i) If there is dissociation of the solute in the solution, the Van’t Hoff factor
will be greater
than one i.e., i > 1.
1+
1
18
1
(ii) If there is association of solute in the solution, the Van’t Hoff factor ‘f’ will be less than
one i.e., i < 1.
19
a) It is due to double bond character in C-Cl bond in Chlorobenzene due to resonance
due to which it id shorter than C-Cl bond
b) Choroform reacts with oxygen in presence sunlight to form poisonous phosgene gas.
It is kept in dark bottles so as to cut off sun light to prevent the formation of
phosgene gas. Or equation
20
a) (CH3)2 NH > CH3NH2 > (CH3)3 N > NH3
b) N-Ethyl-N-methyl ethanamine
21
22
23
a) Native protein is biologically active, whereas denatured protein loses biological
activity and its secondary and tertiary structures are ruptured.
b) Vitamin K.
a) On hydrolysis, sucrose (dextrorotatory) gives glucose (dextrorotatory, + 52.5°) and
1
fructose (laevorotatory, – 92.4°). Since laevorotation of fructose is more than the
dextrorotation of glucose, the mixture is laevorotatory.
b) Amino acids behave like salts rather than simple amines or carboxylic acids
due to 1
the presence of both acidic (-COOH) and basic (-NH2) groups. In solution, the COOH group can lose a proton, and an amine group can accept a proton, giving rise
to a dipolar ion called the Zwitter ion
c) On mild oxidation with bromine water, glucose gives gluconic acid, a six-carbon acid. 1
This indicates that the carbonyl group present in glucose is an aldehydic group.
3
w = 100 mg = 0.100 = 0.1g,
V = 10.0 mL = 0.01 L
π = 13.3 mm Hg = 13.3760 atm
R = 0.0821 L atm mol-1 K-1, M =?
T = 25°C = 25 + 273 = 298 K
24
1
1
1
25
1
b)By Carbylamine test: Methylamine being a primary amine gives this test but
Dimethylamine being a secondary amine does not.
1
1
c)
26
a) Statement
b)
1
½
½
½
½
27
a)Triammine nitrato nickel (II) chloride
1
b) [Co(en)3]3+ is more stable complex than [CO(NH3)6]3+ because of chelate effect.
1
c) Ambidentate ligand : The monodentate ligands with more than one coordinating atoms is
known as ambidentate ligand. Monodentate ligands have only one atom capable of binding
1
to a central metal atom or ion. For example, the nitrate ion NO2– can bind to the central metal
atom/ion at either the nitrogen atom or one of the oxygen atoms.
OR
i) [Fe(en)2Cl2] Cl or x + 0 + 2 (-1) + (-1) = 0
x + (- 3) = 0 or x = + 3
∴ Oxidation number of iron, x = + 3
(ii) The complex has two bidentate ligands and two monodentate ligands. Therefore, the
coordination number is 6 and hybridization will be d2sp3 and shape will be octahedral.
(iii) In the complex 26Fe3+ = 3d5 4s0 4p0
Due to presence of one unpaired electrons in d orbitals the complex is paramagnetic.
The number of geometrical isomers are two.
(v) In coordination complex of [Fe(en)2Cl2] Cl, only cis-isomer shows optical isomerism.
1x
5
(vi) Name of complex: Dichloridobis (ethane-1, 2- diamine) Iron (III) chloride.
28
1
1
1
29
SECTION D
a) The plot of molar conductivity versus square root is a steep curve which can't be
extrapolated to get the value of molar conductivity at infinite dilution. Also, the ionization is
increased with dilution which leads to increase in molar conductivity as infinite dilution can't
reached.
b) Molar conductivity is the property of conductance of a solution containing an electrolyte
mole or is a function of the ionic resistance of a solution or concentration of salt
c)According to Kohlrausch’s law
𝛬mº (MgI2) = 𝛬mº [CH3(COO)]2Mg + 2 𝛬mº (NaI) – 2 𝛬mº (CH3COONa)
𝛬mº (MgI2) = (18.78 + 2 X 12.69 – 2 X 9.10) S cm2 mol-1
𝛬mº (MgI2) = (18.78 + 25.38 – 18.20) S cm2 mol-1
1
1
1
1
𝛬mº (MgI2) = (44.16 – 18.20) S cm2 mol-1
𝛬mº (MgI2) = 25.96 S cm2 mol-1
OR
c)Conductivity = Cell constant / Resistance
1.46 X 10−4 S cm−1 = Cell constant / 1500 Ω
Cell constant = 1.46 X 10−4 S cm−1 X 1500 Ω
Cell constant = 0.219 cm -1
30
1
1
The magnitude of Δ0 decides the actual configuration of d-orbitals with the help of
1
mean pairing energy. If P < Δ0, then pairing of electrons occurs within the same set
and forms low spin complexes due to strong-field ligands. Therefore, it becomes
more energetically favourable for the fourth electron to occupy a t2g orbital with
configuration t2g4 eg0
b) The colour of the complex is due to d-d transition . [Ti(H2O)6]Cl3 on heating
becomes colourless because water is removed on heating [Ti(H2O)6]Cl3 molecule
and in the absence of ligand, crystal field splitting does not occur and hence
substance is colourless
c)
1
a)
1+
1
OR
c) i) When ligand approaches a transition metal ion, the d− orbitals split into two
sets, one with lower energy and the other with higher energy. The difference of
energy between the two sets of orbitals is known as crystal field splitting energy.
ii)Δt = -4/9Δo
31
Compound A to D are,
A = FeCr2O4
B = Na2CrO4
C = Na2Cr2O7.2H2O
D = K2Cr2O7
2
1
4FeCr2O4 + 8Na2CO3 + 7O2 → 8Na2CrO4 + 2Fe2O3 + 8CO2
1
2Na2CrO4 + 2H+ → Na2Cr2O7 + 2Na+ + H2O
1
Na2Cr2O7 + 2KCl → K2Cr2O7 + 2NaCl
OR
1
a) (i) In transition metals besides ns electrons, (n-1)d electrons can also participate in
bonding making stronger metallic bonds. This increases their melting points.
1
ii) Both oxide and fluoride ions are highly electronegative and have a very small size.
Due to these properties, they are able to oxidize the metal to its highest oxidation
1
state.
b) i) The steady decrease in the ionic radius from La3+ to Lu3+ is termed as lanthanoid
contraction.
32
1+
c)
1
a) r = K(2A) (2B)2 ∴ r = 8KAB2 = 8 times
b) Rate expression: The expression which expresses the rate of reaction in terms of
1
molar concentrations of the reactants with each term raised to their power, which
may or may not be same as the stoichiometric coefficient of that reactant in the
balanced chemical equation.
Rate constant: The rate of reaction when the molar concentration of each reactant is
taken as unity
c. log 𝑘2 = 𝐸𝑎 [𝑇2−𝑇1]
𝑘
2.303 𝑅 𝑇 𝑇
1
0.1
log 0.01 =
½
1 2
𝐸𝑎 [1060−1000]
½
2.303 𝑋 8.314𝑋1000𝑋1060
Ea = log10 X 2.303X 8.314X1000X1060 = 338266 Jmol-1 = 338.266 KJ/mole
log A = log K -
½
½
𝐸𝑎
2.303 𝑅𝑇
𝐸𝑎
log A = log K + 2.303 𝑅𝑇
= log (0.01) +
½
338266
2.303 𝑋8.314𝑋 1000
OR
= 15.67
½
a)
½+
½
1
1
1
b)Any two difference
c) Let the rate =k[A]
At t=10 seconds
1
0.04=k[A1]
At t=20 seconds
0.03=k[A2]
∴, in 10 seconds concentration of A decreases by 0.01k[M]
Using first order kinetics equation,
10×k=ln(0.04/k0.03/k)
10×k=0.028
k=0.028
Half life of first order reaction =ln 2k
t1/2=ln 20.028=24.1 seconds
1
33.
1
1
d)CH3COOH + Red P/Cl2
e)C6H5COONa +
NaOH/CaO
ClCH2COOH
C6H6
1
+ Na2CO3
f)Benzophenone< acetophenone< p-tolualdehyde <Benzaldehyde
g) On reaction with NaOH/I2 , Acetophenone forms yellow precipitate of CHI3,while
benzophenone will not give yellow ppt.