Model Question (NEB)
Grade: XII
Full marks: 75 (11 marks Obj+ 64 marks Sub)
Subject: Chemistry (302)
Time: 3 Hours
Group 'A
Time 25 Minutes
'
Multiple Choice Questions (11×1 = 11)
Tick the correct answer.
1. What is the equivalent weight of H3PO3 in the reaction; 2NaOH + H3PO3 → Na2HPO3 +
2H2O
A) 2M
B) M/1
C) M/2
D) M/3
2. The solubility product of chalk is 9.3 × 10-8. What is its solubility in gram per liter?
A) 3.04 × 10-1
B) 3.04 × 10-2
C) 3.04 × 10-3
D) 3.04 × 10-4
3. What is the concentration of N2O5 in the following first order reaction in which the rate is
2.4 × 10-5 mol/L and rate constant is 3.0 × 10-5S-1? 2N2O5 → 4NO2 + O2
A) 0.04
B) 0.8
C) 1.2
D) 1.4
4. What happens when the lead storage battery is discharged?
B) PbSO4 is consumed
A) SO2 is evolved
C) Lead is formed
D) H2SO4 is consumed
5. What is the general electronic configuration of transition metal?
A) (n-1)s2p6d 1-10ns0-2 B) (n-1)s2p6ns2np1 C) (n-1)s2p6d5ns1
D)(n-1)s2p6ns1
6. Which of the following ore is concentrated by forth-flotation process?
A) Hematite
B) Siderite
C) Galena
D) Malachite
7. Which of the following products is obtained when nitrobenzene is electrolytically
reduced?
A) P-aminophenol
B) azobenzene
C) azoxybenzene
D) hydrazobenzene
8. Which of the following compounds is pi-bonded organo-metallic compound which has
ethene as one of its component and is the first synthesized organometallic compound?
A) Zeise‟s salt
B) Ferrocene
C) Dibenzene chromium D) Tetraethyl tin
9. What effect does calcium sulphate have on cement?
A) Retards setting action B) Acts as flux
C) Imparts color D) Reduces strength
10. Removal of which of the following leads to higher fiber-fiber bonding strength in paper? .
A) Softwood
B) Hardwood
C) Lignin
D) Pulp
11. In the figure given below which one is correct?
A) Alpha rays deviate towards A, beta rays deviate towards C and gamma rays direct
towards B.
B) Alpha rays direct towards B, beta rays deviate towards C and gamma rays towards
A.
C) Alpha rays deviate towards C, beta rays direct towards B and gamma rays towards
A.
D) Alpha rays deviate towards C, beta rays deviate towards A and gamma rays direct
towards B.
129
Model Question (NEB)
Grade: XII Subject: Chemistry (302)
Full marks: 75 (11 marks Obj + 64 marks Sub)
Time: 3 Hours
Attempt all the questions.
Group 'B'
Short Answer Questions (8×5 = 40)
1. Standard solution of Na2CO3 is used to determine the strength of H2SO4 during Titration.
A) How is the completion of the reaction in this titration detected? Is the solution
prepared from Na2CO3 primary standard? Why? [1+1]
B) 2.16 g of pure Na2CO3 is added to 400 ml deci-normal solution of H2SO4. How many
B) grams of H2SO4 is further required to neutralize the resultant solution completely? [3]
OR
A) Derive the relation k =log log . Show that for the first order reaction the time required
for half the change (half life period) is independent of the initial concentration.(2+1)
B) A first order reaction is 50% completed in 1.26×10145. How much time would it take
for 90% completion? (2)
2. Study the following data for the thermodynamic process H2O (l) → H2O (s) at different
temperatures and at 1 atmospheric pressure.
Condition
Temperature
Entropy change in J/Kmol-1
Entropy of system
1
2
3
-10C
0oC
+1oC
-25.68
-26.55
-27.62
Entropy of
surrounding
+25.72
+26.88
+27.42
a.
b.
c.
3.
Calculate the total entropy of the universe at given condition 3. (1)
Can we predict the spontaneity of the given reaction at 00C? (1)
Calculate the equilibrium constant for the fusion of ice at 10C. What is the effect of
temperature for the entropy change of reaction? (2+1)
The figure shows the octahedral distortion of d-block orbital in the presence of ligand.
a. Why does octahedral distortion occur in the presence of ligand? Explain on the basis
of CFT. (2)
b. b. On the basis of the given distortion, how can you explain [Cu(H2O)6]++ is blue
colored complex. (1)
c. c. Out of Fe++ and Fe+++ which one is more stable? Explain on the basis of distortion
seen in the above figure. (1)
d. Why do such elements which give such splitting show good catalytic properties? (1)
4. X is an ore of a metal M. X on calcination gives black precipitate (W) of metal oxide
which belongs to group II of basic radical in qualitative analysis. X on roasting gives the
130
metal (M) and a gas as major byproduct. The gas when passed through an acidified
K2Cr2O7 solution turns green.
a. Identify the metal X. (1)
b. Write the reaction involved during calcination of X. (1)
c. Write the action of the gas on acidified K2Cr2O7. (1)
d. Convert metal X into it‟s vitriol. (2)
5. The given table shows the compounds and their molecular formula. How can you convert
P to Q, where Q is a compound in which two methyl groups are substituted at adjacent
carbons? How is P obtained from T, where T is secondary alcohol? Write the reactions
involved in the conversion of P into R and S?
[5x1=5]
Compounds
P
Q
R
S
T
Molecular formula
C 3 H 7 Br
C 6 H 14
CH 2 O
C2H2O
C3H8O
Or
An aromatic compound [A] in which one chlorine atom is substituted at benzene ring. When
the compound [A] is heated with 2, 2, 2-trichloro ethanal in presence of conc. H2SO4 gives an
insecticide [B]. The compound [A] when treated with an acid chloride containing two carbon
atoms in the presence of anhydrous AlCl3 gives [C].
a. Identify B and C.
(1 +1)
b. Reaction of aq. NaOH on the compound [A] is more difficult than with chloroethane,
justify with a suitable explanation. (2)
c. How would you obtain compound A from benzene diazonium chloride? (1)
6. A list of compounds are given as follows:
p-hydroxyazobenzene, C6H5N2Cl, C6H5NH2, C6H5NO2, C6H6
From the above list of compounds, prepare a sequence of reaction chain with suitable
conditions and reactions. (1+1+1+1+1)
7. Write down the isomeric alcohols of C3H8O and their IUPAC name. How would you
apply Victor Meyer's test to distinguish these isomers? (2+3)
8. A) Define condensation polymerization. Write the molecular structures of monomers of
Bakelite.
(1+2)
B) Differentiate between OPC and PPC cement.
(2)
Group 'C'
Long Answer Questions (3 × 8 = 24)
9. (A) What amount of Zn(OH)2 will be precipitated out at 250C if 100 ml of 0.22gm NaOH
is added to 1 liter of a saturated solution of Zn(OH)2? Precipitate is obtained in this
(4+1)
reaction, why? [Solubility product of Zn(OH)2 at 250C is 1.8 x 10-14.]
(B) Potassium hydroxide having pH 8 is diluted 1000 times. Calculate the pH of the
diluted base.
(3)
Or
(A) Calculate heat of formation of ethyl alcohol from the given data.
(4)
Heat of combustion of ethyl alcohol -330 kcal
Heat of formation of Carbondioxide -94 kcal
Heat of formation of water -68.5 kcal
(B) The standard electrode potential for the following electrode reaction at standard state
is given.
Cu(s) → Cu++ (aq) + 2e-……………..E0 Cu++/Cu= +0.34V
Ag+(aq) + e- → Ag(s) …………………..E0 Ag+/Ag=+0.80V
a. Write the cell notation indicating anode and cathode. (1)
131
b. With 1M solution of ion at 250C and 1atm. pressure, what will be the cell potential?
(1)
c. Calculate the free energy change in the reaction. (1)
d. Can we store AgNO3 solution in a copper vessel? (1)
10. (A) A primary alcohol with molecular wt. 46 is boiled with sodium hydroxide and iodine.
When the same alcohol is heated with ethanoic acid in presence of conc. H2SO4, one of
the derivatives of carboxylic acid is obtained. Write the reactions involved in both
conditions. What would be the product obtained when the same alcohol is heated with
conc.H2SO4? How would you distinguish the above alcohol from
methanol?
[1+1+1+1+1=5]
(B) An aromatic compound known as oil of mirabane is prepared from benzene.
a. What product would you obtain when the compound is electrolyzed in acidic
medium?
(1)
b. Give the complete reaction for the conversion of the compound into yellow dye. (2)
11.
(A) An organic compound is used in the given figure to preserve museum specimens
and also to prepare urinary antiseptics.
a. Write the reaction when the compound is heated with concentrated sodium
hydroxide.
(1)
b. Draw the structure of urinary antiseptic
(1)
c. Write the chemical reaction that would occur when the given
preservative is treated with phenol in acidic medium.
(2)
d. How would you obtain the preservative from methanol?
(1)
(B) A carbonyl compound with molecular formula C3H6O (it does
not give silver mirror test) has treated with a compound Y
which gives Z. Z on hydrolysis in acidic medium gives 2hydroxy-2-methyl propanoic acid. Identify the carbonyl compound, Y and Z with
proper reactions.
[1+1+1]
Or
(A) Starting from compound P, how do the reactions
proceed ahead to obtain T which gives benzene
where R is aniline? Complete the reaction sequence
P
T
with suitable conditions.
[5x1=5]
(B) Arrange the given compounds according to their
ascending order of acidic strength and justify your
order.
CH3CH2COOH,
ClCH2CH2COOH
C6H5COOH,
Q
S
R
[1+1+1]
The End
132
Model Question- 1
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group 'A'
Tick the correct answer. (11×1 = 11)
1. What weight of sodium hydroxide is required to neutralize 100 ml of 0.1 N
HCl?
a. 4 g
b. 2 g
c. 0.4 g
d. 0.04 g
2. Ostwald's dilution law is not applicable for
a.CH 3 COOH
b. HCl
c. NH 4 OH
d. HCOOH
3. The addition of a catalyst during a chemical reaction alters which of the
following quantities?
a. Enthalpy
c. Activation energy
b. Entropy
d. Internal energy
4. Which of the following is the concentration of H+ in standard hydrogen
electrode?
a. 1 M
b. 0.01 M
c. 0.1 M
d. 2 M
5. Formation of interstitial compounds makes the transition metals more
a.
soft b. ductile
c. malleable d. none of the above
6. For which of the following ores froth floatation method is used for
concentration?
a. Haematite b. Zinc blende
c. Magnetite d. Camallite
7. Most reactive alkyl halide towards SN1 reaction is
a) n-butyl chloride
b) sec-Butyl chloride
c) tert – butyl chloride
d) iso-butyl chloride
8. When alkane nitrile is hydrolyzed in the presence of dil.acid to give
a) Acid amide
b. Carboxylic acid c. Ester
d. Alcohol
9. Cannizzaro’s reaction is an example of
a. Oxidation reaction
b. reduction reaction
c. disproportionation reaction
d. none of these
10. Which one of the following are Gamma rays.
a. Low energy waves
b. High energy protons
c. High energy electron
d. High energy electromagnetic waves
11. Raw material used for making pulp are
a.wood pulp
b. grasses and reeds c. recycle paper d. all of them
Group 'B'
Short answer questions. (8 × 5=40)
1. a) How is normality differed from molarity?
[1]
b) Write two differences between acid-base titration and redox titration. [2]
c) 0.715 gram of Na 2 CO 3 .xH 2 O required 20 mL of semi normal HCl solution
for complete reaction. Find the value of x.
[2]
Or
133
The following data are given for the reaction: P +Q → Z is first-order w.r.to P
and zero-order w.r.to Q. fill the following table.
Exp. No.
[P], mol L-1
[Q], mol L-1
Rate of formation of (Z) mol
L-1s-1
1
0.1
0.1
2 x 10-2
2
0.2
4 x 10-2
3
0.4
0.4
4
0.2
2 x 10-2
2. Predict the spontaneity of exothermic and endothermic reaction in term of
enthalpy, entropy and free energy change. [5]
3. Cast iron is extacted in a furnace which is known as blast furnace. Write the
chemical reactions involved in the zone of reduction of blast furnace. What
happens when copper sulphate is allowed to react with ammonia solution till
excess? Write the important use of silver. [2+2+1]
4. What are volatile metals? How is steel manufactured by open hearth process?
Explain with well labelled diagram. [1+4]
5. Write the equations for
a) excess ethanol is heated with conc. H 2 SO 4 at 140oC
b) ethanol is heated with excess H 2 SO 4 at 160oC-170oC
c) 2-methylpropan-2-ol vapour is passed through heated copper at 300oC
d) Ethanol is refluxed with SOCl 2 in the presence of pyridine
e) Ethanol reacts with sodium metal
Or
Chloroform is an important chemical compound which has wide scope of
synthetic utility as well as medicinal value, how does chloroform reacts with
a. Zn in the presence of steam
b. Conc. Nitric acid
c. Air in the presence of sunlight
d. Phenol in the presence of NaOH
e. Acetone in the presence of alkali
[1+1+1+1+1]
6. Write the two methods of preparation of chlorobenzene. Why is
nucleophilic substitution in chlorobenzene difficult in comparison to
chloroethane? How is chlorobenzene converted into benzoic
acid? [2+2+1]
7. i) Write the functional isomer of CH 3 COCH 3 and give a chemical
test to distinguish them.
(1+1)
ii) Identify the compound X, Y and Z in the following reaction.
Dry ether
X + CH 3 MgI
H 2 O/H+
Y
Z
X is the aliphatic aldehyde, which can give cannizzaro’s reaction. [1+1+1]
8. What do you mean by OPC and PPC cement? Write down the flow sheet
diagram for the manufacture of portland cement. [3+2]
134
Group 'C'
Long answer questions (3× 8=24)
9. a) What is the solubility product? Write the application of common ion effect
and solubility product.
(1+4)
o
-3
-1
b) The solubility of AgCl in water at 25 C is 1.43x10 gL . Calculate its
solubility in 0.5 M KCl solution.
[3]
Or
a. Draw energy profile diagram for exothermic and endothermic reaction. What
is Gibb's free energy? Derive Gibb's Helmholtz equation. [2+1+1]
a. What is a calomel electrode? Why is this electrode used as a reference
electrode? [2]
b. Give the reason why the blue colour of copper sulphate solution is
0
discharged when an iron rod is dipped in it. Given Ecu2+/cu= 0.34V and
0
[2]
EFe2+/Zn = - 0.44V.
10. i) An alkene (A) on ozonolysis yields acetone and an aldehyde. The aldehyde is
easily oxidized to an acid (B). When (B) is treated with Br 2 /P it yields a
compound (C), which on hydrolysis gives a hydroxyl acid (D). This acid can
also be obtained from acetone by the reaction with HCN followed by
hydrolysis. Identify the compound A, B, C and D.
(5)
ii) How does methanal reacts with
b) Conc.NaOH
(1.5+1.5)
a) NH 3
11. A. Give reason:
a. It is dangerous to boil old sample of ether.
b. Ethers are stored in the bottle containing iron wire.
c. The boiling point of ethers are low as compared to boiling point of
corresponding alcohols.
d. Ethers are commonly used as solvents.
e. Ethers are considered as inert compounds. [1+1+1+1+1]
B. Why is nucleophilic substitution in chlorobenzene difficult in comparison to
chloroethane? How is chlorobenzene converted into benzoic acid? [2+1]
Model Question- 2
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group 'A'
Circle the best alternative to the following questions. [11 × 1 = 11]
Time: 25 mins
1. 10 mL of 10M H 2 SO 4 is diluted to 250 mL, the strength of the diluted solution is
a. 0.80 N
b. 0.40 N
c. 1.0 N
d. 0.60 N
135
N
2. What will be the pH of the solution obtained by mixing 100 c.c. of 10 HCl and 100 c.c. of
N
10 KOH ?
a. 0
b. 7
c. 4
d. 14
3. The unit of rate constant for the second-order reaction is
a. L-1mol S-1
Lmol-1S-1
c. l2mol-2S-1 d. S-1
4. Which statement is correct for given combination in working condition?
a. Combination is in equilibrium
b. electrons flow from anode to cathode
c. current is produced
d. current is consumed
5. Co-ordination number in [Cu(NH 3 ) 4 ]++
a. 2
b.3
c. 4
d. 5
6. Cyanide process is used in the extraction of
a. Gold
b. Silver
c. Both a and b d. copper
7. Reactivity order in nitration is
a. benzene < nitrobenzene < bromobenzene <toluene
b. nitrobenzene > benzene > bromobenzene > toluene
c. benzene > nitrobenzene > bromobenzene > toluene
d. toluene > benzene >bromobenzene > nitrobenzene
8.
Which of the following compounds does not give a tertiary alcohol upon reaction with
methyl magnesium bromide?
a. 3-methylpentanal b. ethyl ethanoate
c. Acetyl chloride
d. 4-heptanone
9. The highest percent in OPC is
a. alumina
b. silica
c. lime
d. iron oxide
7. Which of the following organic compounds turn blue litmus red, produces effervescence
with NaHCO 3 and produces silver mirror with Fehling's solution…
a. CH 3 COOH
b. HCOOH
c. C 6 H 5 OH
d. C 2 H 5 OH
7. When C 6 H 5 N 2 Cl is boiled with water, the resulting organic compound is
a. C 6 H 6 n
b. C 6 H 5 OH
c. C 6 H 5 CHO
d.
C 6 H 5 COOH
8. Nylon-6,6 is ……….polymer
a. addition
b. condensation
c. substation d. none of these
9. Zinc metal is extracted from the ore…..
a. Cinnabar
b. Argentite
c. Copper pyrites
d. Calamine
10. Substance which brings body temperature down are known as
a. antipyretics
b. analgesics
c. antibiotics
d. none
11. Which of the following compounds does not give a tertiary alcohol upon reaction with
methyl magnesium bromide?
a. 3-methylpentanal
b. ethyl benzoate
c. 4,4-dimethylcyclohexane
d. 4-heptanone
136
Group'B'
Short Answer Questions: [8×5=40]
1. Strength of the solution is determined by preparing the standard solution.
a) Differentiate between primary standard solution and secondary standard solution. [2]
b) 'X' g of metal (eq.wt. = 12) was completely dissolved in 100 ml of N/2 HCl. The
volume was then made up to 500ml. 25 ml of this solution requires 17.5 ml of
N/10 NaOH for complete neutralization. Find the value of X.
[3]
OR
a. Write four differences between the order and molecularity of a reaction. [3]
b. For following reaction 2HI →H 2 +I 2. If the rate of formation of I 2 is 9.1 x 10-6 mol
L-1S-1, what will be the rate of disappearance of HI?
[2]
2. What is internal energy? What is entropy of fusion? Heat of formation of ethyl
alcohol, water and carbondioxide are -64.1 Kcal, -68.5 Kcal, and -95 Kcal
respectively. Calculate heat of combustion of ethyl alcohol.[1+4]
3. Write the balanced chemical equation for the reaction in which brown gas is obtained
when copper is treated with conc. nitic acid. The roasted ore of zinc is reduced in a
special type of furnace known as vertical retort furnace. Explain the reduction of the
roasted ore of zinc with well labelled diagram. What happens when white vitriol is
treated with hot and conc. caustic soda solution till excess? [1+2+2]
4. Why transition elements exhibit the variable oxidation state? Define the term i)
coordination number ii) ligand iii) complex compound. [2+1+1+1]
5. Alkyl halides are used for the preparation of a number of other organic compounds.
The most common starting compound in aliphatic organic synthetic are alcohols
which give alkyl halides. The alkylhalide gives a number of organic compounds as
shown in the given reaction sequence.
CH3 CH2 NC
CH3 CH2 CN
Reaction-2
CH3 CH2 OH
Reaction-3
Reaction-1
CH3 CH2 Br
Reaction-4
CH3 CH2 –O- CH3
Reaction-5
CH3 COOCH2CH3
a. For each of the reaction, state the reagent and solvent used.
a.
b.
c.
d.
[1+1+1+1+1]
OR
Benzene diazonium chloride (BDC) is prepared by reacting the primary aromatic
amine with nitrous acid ( NaNO 2 + HCl ) in an ice-cold solution.
Write the chemical reaction that takes place in the preparation of BDC. [1]
Write the use of BDC in the Sandmeyer reaction and Gattermann reaction. [1]
What happens when diazotized solution of aniline is reacted with KI. [1]
Why does Chlorobenzene undergo electrophilic substitution reaction at ortho and
para position. [2]
137
6. The given table shows the compounds sand their molecular formula. The compound
‘A’ is a primary alcohol which gives yellow crystalline ppt. having hospital smell.
The compound ‘D’ converts into propanoic anhydride. Write the reaction involved in
the conversion of compound ‘A’ to propanoic anhydride.
Compound
Molecular formula
A
C2H6O
B
C 2 H 5 Br
C
C3H5N
D
C3H6O2
7. This question is concerned with organonitrogen compounds.
State the reagent needed to produce the two compounds A and B.
NO 2
Reaction-1
A
N
NH2
N
Cl
Reaction-2
B
C
i. What is the reagent for reaction-1 and reaction-2?
[2]
ii. Write the product when compound C is hydrolyzed? [1]
iii. What product would you get when compound A is reduced with LiAlH 4 ?
iv. Convert compound B into p-aminoazobenzene.
[1]
[1]
8. A. Write the molecular structures monomers of following polymers
a. Nylon-6,6
b. PVC
c. Teflon
[1+1+1]
B. Write the basic composition of OPC and PPC.
[1+1]
Group'C'
Long Answer Questions [8 × 3=24]
9. A. What are amphoteric substances? Show that HCO 3 - is an amphoteric
substance. [2+2]
B. The solubility product constant (K sp ) of Ca(OH) 2 at 250C is 4.42 X 10-5. A 500ml
of a saturated solution of Ca(OH) 2 is mixed with an equal volume of 0.4M NaOH.
What mass of Ca(OH) 2 is precipitated out? [4]
Or
A. What is an electrochemical cell? How does it differ from an electrolytic cell? [2]
B. What is standard electrode potential? How does it arise?
[2]
C. The equilibrium constant for the reaction:
N 2 (g) + O 2 (g) ⇌ 2NO (g) at 250C has been found to be 1.0 x10-15. Calculate the
standard free energy change for the reaction.
[2]
D. Under what condition is the reaction expected to occur.
138
i. spontaneous
ii. Non-spontaneous, if both ∆H and ∆S are negative for the reaction? [1+1]
10. A. Arrange the given compounds according to their ascending order of acidic
strength and justify your order.
Phenol, O-nitrophenol, 2, 4, 6-trinitrophenol
[1+1+1]
B. 2, 4, 6-trinitrophenol gives effervescence with NaHCO 3 but phenol does not
why?
[2]
C. What happens when
i. Nitrobenzene is treated with Zn dust and Aq. NH 4 Cl
ii. Nitrobenzene is sulphonated
iii. Nitroethane is reduced catalytically.
[ 1+1+1]
11. i. An alcohol (A) reacts with PCl 5 to produce (B), which on dehydrohalogenation
yields a compound (C), then (C) on ozonolysis gives the mixture of ethanal and
acetone. If the alcohol (A) responses positive iodoform test, identify A, B and C with
related sequence of reactions.
[5]
ii. What is 2,4 – DNP test ?
[2]
iii. Convert acetone into propane.
[1]
OR
A.i. Write down a suitable chemical test to distinguish ethanamine from Nmethylmethanamine [2]
ii. How is ethanamine prepared from
a. Propanamide
b. Ethanenitrile
[1+1]
iii. Convert ethanamine into methanamine [1]
B. Arrange the following compounds in the increasing order of solubility in water and
justify your answer.
C 6 H 5 NH 2, (C 2 H 5 ) 2 NH, C 2 H 5 NH 2,
[1+2]
Model Question- 3
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group 'A'
Tick the correct answer.
(11×1 = 11)
1. 15 ml of N/10 NaOH solution completely neutralizes 12 ml of H 2 SO 4 solution. The
normality of the H 2 SO 4 solution will be
c. N/5
b. N/8
c. N/10
d. N
2. The degree of ionization of an electrolyte depends on upon
a) nature of solvent
b) nature of solute
c) temperature
d) all
3. The rate of a gaseous reaction is given by k[A][B]. If the volume of the vessel
containing these gases is reduced to 1/4th of the initial volume, the rate of reaction
relative to the original rate would be
139
16
1
4
1
a. 1 b.
c.
d.
16
1
8
4. If the oxidation electrode potential of K+/K is +2.93 V. What would be the value of
reduction potential at the same temperature
a. +2.93 V
b. -2.93 V
c. Zero
d. -1.93 V
5. The first transition element is
a. Copper
b. nickel
c. scandium
d. vanadium
6. Malachite is an ore of
(a) iron
(b) copper
(c) zinc
(d) Sliver
7. Tear gas is
a) Chloretone
b) Ethyl carbonate
c) Chloropicrin d) Methylene chloride
8. Ethanol is an isomer of
b) Methoxymethane
b) Propane
c) Ethanol
d) None
9. The lime which has properties of setting are
a. Fat lime
b. hydraulic lime
c. quick lime d. hydrated lime
10. Pulp paper making process was invented in China by
a. Song dynasty b. Tang dynasty
c. Sui dynasty d. Han dynasty
11. Have same atomic numbers but different atomic masses
a. Isotope
b. Atom
c. Radioisotope
d. None of these
Group 'B'
Short answer questions. (8 × 5=40)
1. Concentration of solution is expressed in various ways.
a) Define normal solution and molal solution.
[2]
b) 10 g NaOH was added to 200cc of N/2 (f = 1.5) H 2 SO 4 solution and volume was
diluted to two-liter. Will the resulting solution be acidic, basic, or neutral? [3]
Or
a. What do you mean by catalysis?
[1]
b. The experimental data for the reaction 2A +B 2 →2AB are as below.
Exp. [A] mol L-1
[B] mol L-1
Rate mol L-1s-1
1
0.50
0.50
1.6 × 10-4
2
0.50
1.00
3.2 × 10-4
3
1.00
1.00
3.2 × 10-4
(i) Find the overall reaction and rate constant.
[2]
(ii) Calculate the rate of formation of AB when the initial concentration of A and B
are 2 mol L-1 and 4 mol L-1 respectively.
[2]
2. What is entropy of fusion? State and explain second law of thermodynamics.[1+4]
3. What is tailing of mercury? Mention the factors affecting the formation of complex
compound by transition elements. What is crystal field splitting? [1+2+2]
140
4. Why does zinc become dull in contact with moist air? What happens when corrosive
sublimate is allowed to react with stannous chloride till excess? Write the name of any
two important ore of copper with molecular formula. [2+2+1]
5. write the possible isomers for the formula C 2 H 6 O. write their IUPAC name. which of
the isomer is soluble in water and higher boiling point and why? And write the
chemical test to distinguish from methanol?
Or
The Chloroform can be prepared by heating paste of bleaching powder with ethanol
or acetone. What happens when,
a) Chloroform is warmed with aniline and alc. KOH. [1]
b) Chloroform is boiled with KOH solution.
[1]
c) Chloroform is warmed with phenol and aqueous alkali. [1]
d) Chloroform is exposed to sunlight and air for long time. [1]
e) Chloroform is heated with Conc.HNO 3 .
[1]
6. Draw the structure of possible isomers of C 4 H 8 O 2 . Also write their IUPAC name.
Why do carboxylic acid not show positional isomers?
7. Nitro
8. Cement
Group 'C'
Long answer questions
(3× 8=24)
9. a) How Bronsted –Lowry defines acid and base. What are its advantage and
limitation?
b) The solubility of AgCl in water at 298 K is 1.43 × 10-3 g/ltr. Calculate its solubility in
0.5 M KCl solution. (Ag = 108). Also, calculate the ppt formed.
[2+2+4]
Or
a. Calculate the enthalpy of formation of naphthalene from the following data:
C (s) + O 2(g) → CO 2(g) : ∆H = -94.405 Kcal
2H 2 (g) + O 2(g) → 2H 2 O(1) : ∆H = -136.6 Kcal
C 10 H 8 (s) + 12O 2 (g)→ 10 CO 2 (g) + 4H 2 O(l) ∆ H = -1231.5 Kcal
[4]
b. i. What is a standard hydrogen electrode?
[1]
++
++
ii. For a cell: Mg(s)/Mg (1M)//Cu (1M)/Cu(s)
Given, Eo Mg++/Mg = -2.37V and Eo Cu++/Cu = +0.34V
(i) Indicate anode and cathode.
[1]
(ii) Write the reaction taking place at electrode
[1]
(iii) Calculate the EMF at 1M solution of its ion.
[1]
10. You have ethanol, propan-2-ol and 2-methylpropan-2-ol in separate test tube. How
would you distinguish them by using Victor’s Meyer’s method. Write all the reaction
involved. And what are the oxidized products of them.
11. A. An organic liquid (A) reacts with sodium nitrite and dil. Hydrochloric acid in ice
bath to give compound (B) which on warming with cuprous chloride in dil. HCl gives
compound (C). When (C) is heated with NaOH at about 3500C under high pressure
followed by acidification, (D) is formed. (D) reacts with aqueous bromine to give
white precipitate (E) which on heating with Zn dust gives 1,3,5-tribromobenzene.
Identify A, B, C, D and E with necessary chemical reactions. [5]
141
B. Draw the structure of possible isomers of C 4 H 8 O 2 . Also write their IUPAC name.
Why do carboxylic acid not show positional isomers? [3]
Model Question- 5
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group 'A'
Tick the correct answer. (11×1 = 11)
1. What weight of sodium hydroxide is required to neutralize 100 ml of 0.1 N HCl?
a. 4 g
b. 2 g
c. 0.4 g
d. 0.04 g
2. Ostwald's dilution law is not applicable for
a.CH 3 COOH
b. HCl
c. NH 4 OH
d. HCOOH
3. The addition of a catalyst during a chemical reaction alters which of the following
quantities?
a. Enthalpy
c. Activation energy
b. Entropy
d. Internal energy
4. Which of the following is the concentration of H+ in standard hydrogen electrode?
a. 1 M
b. 0.01 M
c. 0.1 M
d. 2 M
5. Formation of interstitial compounds makes the transition metals more
b.
soft
b. ductile
c. malleable d. none of the above
6. For which of the following ores froth floatation method is used for concentration?
a. Haematite
b. Zinc blendec. Magnetite d. Camallite
7. Most reactive alkyl halide towards SN1 reaction is
a) n-butyl chloride
b) sec-Butyl chloride
c) tert – butyl chloride d) iso-butyl chloride
8. When alkane nitrile is hydrolyzed in the presence of dil.acid to give
b) Acid amide
b. Carboxylic acid
c. Esterd. Alcohol
9. Cannizzaro’s reaction is an example of
a. Oxidation reaction
b. reduction reaction
c. disproportionation reaction
d. none of these
10. Which one of the following are Gamma rays.
a. Low energy waves
b. High energy protons
c. High energy electron
d. High energy electromagnetic waves
11. Raw material used for making pulp are
a.wood pulp
b. grasses and reeds
c. recycle paper
them
142
d. all of
Group 'B'
Short answer questions.
(8 × 5=40)
1. a) How is normality differed from molarity?
[1]
b) Write two differences between acid-base titration and redox titration. [2]
c) 0.715 gram of Na 2 CO 3 .xH 2 O required 20 mL of semi normal HCl solution for
complete reaction. Find the value of x.
[2]
Or
The following data are given for the reaction: P +Q
zero-order w.r.to Q. fill the following table.
Exp. No.
[P], mol L-1
[Q], mol L-1
1
2
3
4
0.1
0.4
-
0.1
0.2
0.4
0.2
→ Z is first-order w.r.to P and
Rate of formation of (Z) mol L1 -1
s
2 x 10-2
4 x 10-2
3 x 10-2
2. Predict the spontaneity of exothermic and endothermic reaction in term of enthalpy,
entropy and free energy change. [5]
3. Cast iron is extacted in a furnace which is known as blast furnace. Write the chemical
reactions involved in the zone of reduction of blast furnace. What happens when
copper sulphate is allowed to react with ammonia solution till excess? Write the
important use of silver. [2+2+1]
4. What are volatile metals? How is steel manufactured by open hearth process? Explain
with well labelled diagram. [1+4]
5. Write the equations for
f) excess ethanol is heated with conc. H 2 SO 4 at 140oC
g) ethanol is heated with excess H 2 SO 4 at 160oC-170oC
h) 2-methylpropan-2-ol vapour is passed through heated copper at 300oC
i) Ethanol is refluxed with SOCl 2 in the presence of pyridine
j) Ethanol reacts with sodium metal
Or
Chloroform is an important chemical compound which has wide scope of synthetic
utility as well as medicinal value, how does chloroform reacts with
f. Zn in the presence of steam
g. Conc. Nitric acid
h. Air in the presence of sunlight
i. Phenol in the presence of NaOH
j. Acetone in the presence of alkali
[1+1+1+1+1]
6. Write the two methods of preparation of chlorobenzene. Why is nucleophilic
substitution in chlorobenzene difficult in comparison to chloroethane? How is
chlorobenzene converted into benzoic acid? [2+2+1]
7. i) Write the functional isomer of CH 3 COCH 3 and give a chemical
test to distinguish them.
(1+1)
ii) Identify the compound X, Y and Z in the following reaction.
H 2 O/H+
Dry ether
X + CH 3 MgI
Y
Z
X is the aliphatic aldehyde, which can give cannizzaro’s reaction. [1+1+1]
143
8. What do you mean by OPC and PPC cement? Write down the flow sheet diagram for
the manufacture of portland cement. [3+2]
Group 'C'
Long answer questions
(3× 8=24)
9.a) What is the solubility product? Write the application of common ion effect and
solubility product.
(1+4)
c) The solubility of AgCl in water at 25 oC is 1.43x10-3 gL-1. Calculate its solubility in
0.5 M KCl solution.
[3]
Or
b. Draw energy profile diagram for exothermic and endothermic reaction. What is
Gibb's free energy? Derive Gibb's Helmholtz equation.
[2+1+1]
d. What is a calomel electrode? Why is this electrode used as a reference electrode?
[2]
e. Give the reason why the blue colour of copper sulphate solution is discharged
0
0
when an iron rod is dipped in it. Given Ecu2+/cu= 0.34V and EFe2+/Zn = - 0.44V.
[2]
10. i) An alkene (A) on ozonolysis yields acetone and an aldehyde. The aldehyde is easily
oxidized to an acid (B). When (B) is treated with Br 2 /P it yields a compound (C),
which on hydrolysis gives a hydroxyl acid (D). This acid can also be obtained from
acetone by the reaction with HCN followed by hydrolysis. Identify the compound A,
B, C and D.
(5)
ii) How does methanal reacts with
a) NH 3
b) Conc.NaOH
(1.5+1.5)
11. A. Give reason:
a. It is dangerous to boil old sample of ether.
b. Ethers are stored in the bottle containing iron wire.
c. The boiling point of ethers are low as compared to boiling point of corresponding
alcohols.
d. Ethers are commonly used as solvents.
e. Ethers are considered as inert compounds.
[1+1+1+1+1]
B. Why is nucleophilic substitution in chlorobenzene difficult in comparison to
chloroethane? How is chlorobenzene converted into benzoic acid?
[2+1]
144
Model Question- 6
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group A: Multiple Choice Questions ( 11 * 1 = 11)
Time 25 Minutes
Tick the correct answer.
1. Phenolphthalein is not a good indicator for titrating
a. NaOH against oxalic acid
c. NaOH against H 2 SO 4
b. Oxalic acid against KMnO 4
d.NaOH against HCl
2. All electrophiles are
a) Arrhenius acid
b) Bronsted base
acid
3. For a reaction, t 1/2 α the order of the reaction is
a) 0
b) 2
4. . Ore of aluminium is
(a) bauxite
(b) hematite
5. Atomic radii of d-block elements in a series
a.
b.
c.
d.
c) Lewi’s base
d) Lewi’s
c) 1
(c) dolomite
d) 3
(d) None of these
decreases with increase in atomic number
increases with increase in atomic number
remains constant
none of the above
6.
Which of the following sulphides when heated strongly in air gives the corresponding
metal without undergoing separate reduction of oxide?
(a) Cu 2 S
(b) FeS
(c) HgS
(d) ZnS
7.
What product is obtained when nitromethane is heated with chlorine in presence of
NaOH
(a) Chloropicrin
8.
(b) Methanamine
(c) Chloretone
(b) R 2 CuLi
(c) RLi
(d) Ethanamine
Gilman’s reagent is,
(a) R 2 Cd
(d) RMgX
9. Radioactive has an unstable nucleus and undergoes radioactive decay.
a. Isotope
b. Atom
c. Radioisotope
d. None of these
10. Before final drying of paper, the amount of H 2 O is reduced to
(a) 5-6%
(b) 99.5%
(c) 60-65%
(d) 10%
11. The drugs used for the treatment of thyroid fever is
a) Novalgin
(b) Quinoline
(c) Chloromycetin (d) Paracetamol
145
Group 'B'
Short Answer questions. (Attempt all the questions)
11. Volumetric analysis is a quantitative method in which based on the law of equivalence?
a) Define endpoint and equivalence point.
[2]
b) 4 gm of divalent metal was dissolved in 100 cc of 2M H 2 SO 4 (f = 1.01). The excess
acid requires 30 cc of 1N NaOH for complete neutralization. Find the atomic mass of
metal.
[3]
2. Draw energy profile diagram for exothermic and endothermic reaction. What is Gibb's
free energy? Derive Gibb's Helmholtz equation. What is standard heat of formation?
[2+1+1+1]
3. What is zinc spelter? Write the important characteristics of transition elements. Why is the
mcompound of zinc coloursless?
[1+3+1]
4. TWhat happens when caustic soda is treated with i. calomel ii.corrosive sublimate? Name
one important ore of iron with molecular formula. What is blister copper? Write one use
of white vitriol.
[2+1+1+1]
5. When 2-bromopentane reacts with alc.KOH, pent-2-ene is formed as the major product,
write the reaction. Which rule predicts the major product ? State the rule and write the
justification for the rule. Convert 2-Chloropropane to 1-Chloroprapane. [1+1+1+2]
OR
Prepare propan-1-ol, propan -2-ol, 2-methyl propan -2-ol and benzoic acid by using
Grignard reagent. What products would you expect to get by the action of water on npropyl magnesium iodide ?
(4+1)
6. When benzamide is allowed to react with bromine in presence of KOH solution, it gives
the compound which is steam volatile in nature.
a. Write down the reaction involved and identify the compound
[2]
b. What happens when the compound is warmed with chloroform and alcoholic
potassium hydroxide?
[1]
c. How would you convert the compound into orange red dye?
[2]
7.
Ethyl alcohol is alcoholic beverages that can be manufactured by fermentation process.
So prepare ethyl alcohol in industrial sector.
[5]
8. What is azo – dye? Write any two characteristics of dyes with suitable examples.
[3]
Differentiate between thermoplastics and thermosetting plastics with suitable examples. [2]
Group 'C;
Long Answer questions.
9. a) How strong electrolyte differs from the weak electrolyte. Derive the mathematical
equation for Ostwald's dilution law.
(2+3)
b) What is conjugate acid-base pair? Write the conjugate acid-base pair of H 2 S and
NH 3 .
(3)
OR
a) What is a calomel electrode? Why is this electrode used as a reference
electrode?
[2]
146
b)
Give the reason why the blue colour of copper sulphate solution is discharged when
0
0
an iron rod is dipped in it. Given Ecu2+/cu= 0.34V and EFe2+/Zn = - 0.44V.
[2]
c) Given that,
0
0
0
EZn2+/Zn = - 0.76V,
EAg+/Ag = 0.80V
Ecu2+/cu = +0.34V,
Can we store:
i. Copper sulphate solution in zinc vessel?
ii. Copper sulphate solution in a silver vessel?
Give a suitable explanation.
[2+2]
10. Write the equations for
(5)
i)
a) excess ethanol is heated with conc. H 2 SO 4 at 140oC
b) ethanol is heated with excess H 2 SO 4 at 160oC-170oC
c) 2-methylpropan-2-ol vapour is passed through heated copper at 300oC
d) Ethanol is refluxed with SOCl 2 in the presence of pyridine
e) Ethanol reacts with sodium metal
ii. write short notes on:
(3)
a) Kolbe reaction
b) Reimer-Tiemann reaction
11. i) Compound “A” (C 5 H 12 O) does not react with phenyl hydrazine. Oxidation of “A” with
K 2 C r2 O 7 /H+ gives “B” (C 2 H 10 O). Compound “B” reacts with phenyl hydrazine but
does not give Tollen’s test. The original compound “A” can be dehydrated with
H 2 SO 4 give a hydrocarbon “C” (C 5 H 10 ). Ozonolysis of the hydrocarbon “C” give
acetone and acetaldehyde. Identify compounds A, B and C.
(5)
ii) Convert acetone to methanal.
(2)
iii) What happens when ethanal is treated with saturated solution of Sodium
bisuphite ?
(1)
OR
A) Methanoic acid is the first member of the monocarboxylic acid and shows many reactions
of an aldehyde. How does formic acid resembles with aldehyde? Explain with reason and
necessary reactions
(5)
B) Give reasons
a) Chloroacetic acid is stronger acid than acetic acid
(1.5)
b) The molecular weight of acetic acid is 60 but practically calculated as 120. (1.5)
END
Model Question- 7
Chemistry XII
Time :3 hours
Attempt all questions
Full marks: 75
Group 'A'
Circle the best alternative to the following questions. [11 × 1 = 11]
1.
A solution contains 4 g of NaOH in 2 liters of solution, its normality is
2.
a. 0.1 N
b. 0.0125N
The pH of 0.02 M NaOH is
c. 0.125 N
147
d. 0.5 N
Time: 25 mins
3.
a. 1
b. 10.3
c. 12.3
d. 13.3
Which of the following statements is incorrect about the collision theory of chemical
reaction?
b. It considers reacting molecules or atoms to be hard spheres and ignores their
structural features.
c. Number of effective collisions determines the rate of reaction.
d. Collision of atoms or molecules possessing sufficient threshold energy results in
product formation.
e. Molecules should collide with sufficient threshold energy and proper orientation for
the collision to be effective.
4.
5.
The cell used in a cellphone is
a. primary cell
b. secondary cell
c. fuel cell
d. galvanic cell
The density of transition metals in a series
a. decreases gradually
b. increases gradually
c. remains constant
d. may increase or decrease
6. Which of the following slags is produced during extraction of iron?
b. FeSiO 3
c. MgSiO 3
d. ZnSiO 3
a. CaSiO 3
7. Reactivity order in nitration is
a. benzene < nitrobenzene <bromobenzene<toluene
b. nitrobenzene > benzene >bromobenzene> toluene
c. benzene > nitrobenzene >bromobenzene> toluene
d. toluene > benzene >bromobenzene> nitrobenzene
8. Reaction between methyl magnesium bromide and carbondioxide gives
a.CH 3 COOH
b.CH 3 CHO
c. HCOOH
d.CH 3 CH 2 OH
9.
The colored cement(white cement ) consists of ………. Percentage of pigment
a. 2-4
b. 8-12
c. 4-10
d. 5-10
10. The reaction of alcoholysis of ester is called
a) Esterfication
b)Trans-esterification
c) Saponification d) Hydrolysis
11. Phenol on treatment with conc. HNO 3 in the presence of conc. H 2 SO 4 gives
a) m-nitrophenol
b) O- nitrophenol
c) p- nitrophenol d) Picric acid
Attempt all the questions:
Group' B '
Short Answer Questions: [8×5=40]
1. What is equivalent weight? What volume of 95% sulphuric acid (density = 1.85 g/cc)
and what mass of water must be taken to prepare 100 cc of 15% Solution of sulphuric
acid (density = 1.1 g/cc)?
[1+4]
OR
a. Define the half-life period of a reaction. The half-life periods of two reactions A
and B are 3.21x 102 minute and 569 minutes respectively. Which of these is a faster
reaction? [3]
b. What is enzyme catalysis.write its characteristics.
[2]
148
2. Under what condition is the reaction expected to occur.
a. spontaneous
b. Non-spontaneous, if both ∆H and ∆S are positive for the reaction?
c. Calculate the enthalpy of formation of NH3 from the following
equation.
N 2 (g) + 2H 2 (b) → 2NH 3 (g) : ∆H = -186 KJ
Define enthalpy of reaction.
[2+2+1]
3. Why most of the transition elements exhibit the catalytic property? How is calomel
prepared? Write a balanced chemical equation involved. Write the action of heat on
blue viriol.
[2+1+2]
4. Draw a well labelled diagram for roasting and distillation during the extraction of
mercury from cinnabar. What is lithopone? Write its one important use. Write the
chemical reaction involved in zone of combustion of blast furnace during the
extraction of cast iron.
[2+2+1]
5. An organic compound (A) C 2 H 6 O reacts with sodium to form a compound (B) with
evolution of H 2 gas and gives a yellow compound (C) when heated with I 2 and
0
NaOH. When (A) is heated with conc. H 2 SO 4 at 140 C it gives a compound (D)
C 4 H 10 O which on treatment with excess of conc. HI gives (E). (D) is also obtained
when (B) is heated with (E). Identify (A), (B), (C), (D) and (E) and write the reaction
involved.
[1+1+1+1+1]
OR
Chloroalkane is hydrolysed easily with aqueous NaOH but Chlorobenzene requires
high temperature and high pressure. Give the proper reason. What happens when
chlorobenzene is heated with Na metal in the presence of dry ether? Convert
chlorobenzene into 1,3-dichlorobenzene.
[2+1+2]
6. Write the equations for
a) Excess ethanol is heated with conc. H 2 SO 4 at 140oC
b) Ethanol is heated with excess H 2 SO 4 at 160oC-170oC
c) 2-Methylpropan-2-ol vapour is passed through heated copper at 300oC
d) Ethanol is refluxed with SOCl 2 in the presence of pyridine
e) Ethanol reacts with sodium metal
[1+1+1+1+1]
7. Identify compounds A, B and C in the following sequence of reactions.
[3]
i. Write the product when compound B is hydrolyzed?
[1]
ii. What product would you get when compound A is reduced with LiAlH 4 ?
[1]
8.A.What is condensation polymerization? what are the starting materials for
a. Nylon 66
b. Dacron
c. Bakellite
149
[3]
[1+1+1]
B. what is the basic composition of Portland cement. What raw material is used
[1+1]
in the manufacture of this cement? Describe method
Group-C
Long Answer Questions [3 x 8=24]
9.
i. What happens when HCl gas is passed through an impure solution of common salt?
[2]
ii. write short notes on salt hydrolysis.
[3]
iii. The solubility product of AgCl in water is 1.0 x 10-10 at 250C. Calculate its
solubility
a) pure water
b) 0.02 M KCl solution c) ppt of AgCl in g/l [Ag=108, Cl=35.5]
(3)
OR
E. What is fuel cell? Write short notes on hydrogen- oxygen fuel cell.
F. Distinguish between extensive and intensive properties.
[4]
[2]
G. The latent heat of fusion of ice is 336J/g. Calculate the molar entropy of
fusion of ice at its melting point.
[2]
10 A. Chloroacetic acid is stronger acid than acetic acid, why?
[2]
1. The molecular weight of acetic acid is 60 but practically calculated as 120.Give
reason.
[2]
C. What happens when
i. Nitrobenzene is electrolyzed in acidic medium
ii. Phenol is treated with excess of aq. Bromine.
iii. Phenol is treated with conc. HNO 3 in presence of conc. H 2 SO 4 .
iv. 2-methylpropan-2-ol vapour is passed through heated copper at 300oC.
[ 1+1+1]
11. i. An organic compound (A) react with PBr 3 to give (B). Compound (B) produces
(C)when heated with alc. KOH. The compound (C) undergoes ozonolysis to yield
ethanal and methanal as major products. The compound (A) responses iodoform test.
Identify A, B, C and write reactions involved. How is (A) obtained from CH 3 MgBr.
(4+1)
ii.
Give a chemical test to distinguish between benzaldehyde and
formaldehyde.
[2]
iii
Convert acetaldehyde into lactic acid.
[1]
OR
A nitrogen containing compound evolved very bad smell on heating with CHCl 3 and
alc. KOH.
a. Identify the compound. What happens when that compound is treated with
phenyldiazonium chloride salt in presence of acid?
[1+2]
b. Why primary amines have higher boiling point than tertiary amines? [2]
c. Why primary amines have higher boiling point than tertiary amines? [2]
d. Arrange the following compound in the decreasing order of basic strength.
C 6 H 5 NH 2, (CH 3 ) 2 NH, CH 3 NH 2, (CH 3 ) 3 N
150
Model Question- 8
Chemistry XII
Time :3 hours
Full marks: 75
Attempt all questions
Group 'A'
Tick the correct answer.
(11×1 = 11)
1.Equivalent weight of KMnO 4 in acidic medium is
c) 31.6
b. 13.8
c. 52.6
d. 15
2. For Cu (OH) 2 , K sp = 1.6 x 10-19. What is the molar solubility of Cu (OH) 2 ?
b. 2.7 x 10-11 M
c. 6.4 x 10-7 M
d. 5.1 x 10-10 M
a. 3.4 x 10-7 M
3. A first-order reaction is 50% completed in 1.26 × 1014 s. How much time would it
take for 100% completion?
a. 1.26 × 1015 s b. 2.52 × 1028 s c. 2.52 × 1014 s
d. infinite
4. While charging the lead storage battery.
a. PbSO 4 anode is reduced to Pb.
b. PbSO 4 cathode is reduced to
c. Pb.PbSO 4 cathode is oxidized to Pb.
d.PbSO 4 anode is oxidized to PbO 2 .
5. In industrial processes, transition elements and their oxides are used as
a. surfactants
b. insecticides
c. catalyst
d. any of them
6. In blast furnace iron oxide is reduced by
a. silica
b. carbon monoxide c. carbon
d. lime stone
7. The addition of 1% ethanol to bottle of chloroform acts as
a. Positive catalyst
b. Negative catalyst c. Biocatalyst d. Autocatalyst
8. The bond angle of C-O-C in ether is about
a. 1800C
b. 109.50C
c. 1100C
d. 1050C
9. Gypsum is used in cement for
a. Colour
b. strength
c. controlling setting time d. none
10. Half-rag paper usually contains
a. 50% rag fibre and 50% cellulose b. 25% ragfibre and 75% cellulose
c. 75% ragfibre and 25% cellulose
d. none
11. Penetrating power of proton is
a. Greater than electron
c. Greater than neutron
b. Lesser than electron
d. None
Group 'B'
Short answer questions. (8 × 5=40)
12. Define acidity and basicity.1.4 gm of dolomite (a mixture of CaCO 3 and MgCO 3 ) was
dissolved in 200ml of 0.2 N HCl solution. After the reaction was completed; the
resulting solution was diluted to 250 ml and 10 ml of this solution required 12 ml of
N/30 NaOH Solution for Neutralization. Calculate the percentage composition of the
mixture.
[1+4]
Or
151
What is meant by proper orientation and effective collision? What will be the initial
rate of reaction if its rate constant is 1 x 10-3 min-1 and the concentration of the
reactant is 0.2 mol l-1. How much the reactant will be converted into the product in
500 minutes?
[2+3]
13. Distinguish between extensive and intensive properties. State Hess's law of constant
heat summation. The latent heat of fusion of ice is 336J/g. Calculate the molar entropy
of fusion of ice at its melting point.
[2+1+2]
14. What are the main assumptions of CFT? Explain the crystal field splitting in
octahedral complexes.
[3+2]
15. Draw a well labelled diagram for roasting and distillation during the extraction of
mercury from cinnabar. What is lithopone? Write its one important use. Write the
chemical reaction involved in zone of combustion of blast furnace during the
extraction of cast iron.
[2+2+1]
16. Match the items of column I and II [0.5+0.5+0.5+0.5+0.5]
Column I
Column II
i.
S N 1 reaction
a. Fittig reaction
ii.
Chloroform and Acetone
b. Wurtz-Fittig reaction
iii.
Biphenyl
c. 30< 20 < 10 haloalkanes
d. Saytzeff’s rule
iv.
Chlorobenzene and Chloral
v.
Elimination of HX from alkyl halide
e. Chorobromocarbons
f. Racemization
g. Sleeping tablets
h. DDT
Write the reaction for each match. [0.5+0.5+0.5+0.5+0.5]
Or
What happens when ethoxy ethane treated with
a. Cl 2 in dark
b. Cl 2 in light
c. Air and light
d. Cold and conc. H 2 SO 4
e. Excess HI/Δ
17. A list of compounds are given as follows:
Phenylacetic acid, toluene, benzyl cyanide, benzene, benzyl chlode
From the above list of compounds, prepare a sequence of reaction with suitable
conditions and reactions.
18. Write the equations for
a) excess ethanol is heated with conc. H 2 SO 4 at 140oC
b) ethanol is heated with excess H 2 SO 4 at 160oC-170oC
c) 2-methylpropan-2-ol vapour is passed through heated copper at 300oC
d) Ethanol is refluxed with SOCl 2 in the presence of pyridine
e) Ethanol reacts with sodium metal
19. A. Mention an important function of each of the followings:
i. Antipyretic
ii. PVCiii. Dacron
152
B. Write the application of 60Co and 99Te.
Group 'C'
Long answer questions
(3× 8=24)
20. a) What is the solubility product principle. discuss three conditions of solubility
product principle.
[2]
-8
b) Calculate the pH of 1×10 M HCl solution. [2]
c) Calculate the pH of 0.1 M acetic acid (Ka = 1.8 x 10-5) [2]
d) The solubility of AgCl in water at 250C is found to be 1.06 x 10-5 mole L-1.
Calculate the solubility product of AgCl at this temperature.
[2]
Or
a. The heat of formation of carbon dioxide, water and glucose are -395, -269 and
-1169KJ respectively. Calculate the heat of combustion of glucose.
[ 4]
b. What are secondary cell. Describe about Lead storage batteries.
[4]
21. A) Arrange the given compounds according to their ascending order of acidic strength
and justify your order.
Phenol, O-nitrophenol, 2, 4, 6-trinitrophenol
[1+2]
B) 2, 4, 6-trinitrophenol gives effervescence with NaHCO 3 but phenol does not
why?
[2]
C) Convert Phenol to Aspirin. Write the use of Aspirin [2+1]
11. Identify the compounds A, B, C and D in the following sequence of reactions.
Benzaldehyde
Conc. HNO3
Sn/ HCl
A
B
Conc. H2SO4
NaNO2+ HCl
+
C
H2O/ H
0
0-5 C
Conc
ii) Convert benzadehyde to benzene.
iii) Prepare benzaldehyde from benzal chloride.
[4+2+2]
Or
a. Write down the structure and IUPAC name of isomeric amines of molecular
formula C 3 H 9 N. how would you separate them from the mixture by
Hoffmann’s method? [2+3]
b. What happens when ethanoic acid is
i. Reacted with NaHCO 3
ii. Refluxed with SOCl 2
iii. Reduced with LiAlH 4
[1+1+1]
153
D
Model Question- 9
Chemistry XII
Time :3 hours
Full marks: 75
Group 'A'
Circle the best alternative to the following questions. [11 × 1 = 11]
Time: 25 mins
1.
If 20 ml of 0.25 N strong acid and 30 ml of 0.2 N of the strong base are mixed, then the
resulting solution is
a. 0.25 N acidic
b. 0.25 N basic
c. 0.2 N acidic
d. 0.2 N basic
2.
H 2 O is
3.
a) Bronsted acid
b) Bronsted base
c) neutral
d) both a and b
−2 −1
The rate constant of a reaction is 5.8 × 10 s . The order of the reaction is
a) First order
b) Second order
c) zero order
d) Third order
4. What is the function of the salt bridge?
a. hold the cell together
b. balance the charges to keep the solutions neutral
c. where oxidation occurs
d. where reduction occurs
5. Paramagnetism is common in
a. s-block elements
c. d-block elements
b. p-block elements
d. any of them
6. Which of the following sulphides when heated strongly in air gives the corresponding
metal without undergoing separate reduction of oxide?
b. FeS
c. HgS
d. ZnS
a. Cu 2 S
7. What product is obtained when nitromethane is heated with chlorine in presence of NaOH
a. Chloropicrin
b. Methanamine
c. Chloretone
d. Ethanamine
8.
Which of the following is an Organo metallic compound ?
a. CH 3 COONa
b. CH 3 ONa
c. (CH 3 CH 2 ) 2 Zn d. CH 3 CH 2 COOAg.
9. White cement does not have
a. Fe
b. Si
c. Ca
d. Al
10. Which of the following chemical can be used for bleaching the paper ?
a. hydrogen peroxide
b. Conc.H 2 SO 4
c. Na 2 CO 3
d. H 3 PO 4
11. Which one of the following has no charge?
a. Gamma rays
b. Beta rays
c. Alpha rays
d. Cathode rays
Attempt all the questions:
Group 'B'
Short Answer Questions: [8×5=40]
1. a) Define indicator. Which indicator do you use in a titration of oxalic acid and sodium
hydroxide?
(1+1)
154
b) 7.5 g of dibasic acid is dissolved in water and the solution is made up to 250 cc. 25
cc of this acid requires 16.3 cc of 1N NaOH for complete neutralization. Calculate
the molecular weight of acid.
OR
For a gaseous reaction A + B → C+ D it is found that Rate =K[A]2[B] how many
times the rate of reaction increased or decreased if
a. The partial pressure of both A and B is doubled.
b. Partial pressure of A double but B remains constant.
c. The volume of reacting vessels is doubled.
d. Inert gas is added to the reaction.
e. Temperature is raised by 30o C.
[1+1+1+1+1]
2. When the reaction is carried out at non-standard condition, the free energy change differs
from standard free energy change.
What is Gibb's free energy? How standard free energy is related with equilibrium
constant. The equilibrium constant for the reaction PCl 5 (g)↔PCl 3 (g) + Cl 2 (g) at 298K
has been found to be 1.8 × 10 -7. Calculate ΔG° for the reaction.
[1+2+2]
3. What is copper matte? What happens when calomel is treated with aqua regia solution?
Draw a well-labelled diagram for the manufacture of steel by Bessemer's process? Why
does copper turn into green when exposed to air for the long period of time? [1+1+2+1]
4. Write short note on crystal field theory. Mention any two ways to prevent rusting of
iron.
[3+2]
5. Treatment of 2-bromobutane with hot alcoholic KOH gives a mixture of two isomeric
butenes (A) and (B). Ozonolysis of the minor product gives methanal and another
aldehyde (C) in equimolar proportions whereas major alkene gives single product (D) on
ozonolysis. What are the structural formulas of A, B, C and D. Give equations for all
reactions.
[5]
OR
Give reason:
a. It is dangerous to boil old sample of ether.
b. Ethers are stored in the bottle containing iron wire.
c. The boiling point of ethers are low as compared to boiling point of corresponding
alcohols.
d. Ethers are commonly used as solvents.
e. Ethers are considered as inert compounds.
6. This question is related to the organic compound containing hydroxyl as functional
group.
i. Write a reaction which distinguish primary alcohol from secondary alcohol.[2]
ii. Write the isomer of alcohol having molecular formula C 3 H 8 O which gives
positive iodoform test.
[2]
iii. How can you prepare ethanol from cane sugar? Write a reaction only.
[1]
7. A nitrogen containing compound evolved very bad smell on heating with CHCl 3 and
alc. KOH.
a. How that compound is nitrated?
[3]
b. What happens when that compound is treated with phenyldiazonium chloride salt
in presence of acid?
[2]
8. A. What are natural and synthetic polymers? Give one example of each. What are the
monomer of nylon-6,6? [1+1+1]
B. Write the name of any two fibrous and non-fibrous raw material for paper. [2]
155
Group'C'
Long Answer Questions [3×8=24]
9. a) Define ionic product, pH, and pOH of a solution.
(3)
b) what is a buffer solution? Give the example of acid and basic buffer solution (2)
c) What mass of KOH should be dissolved in 1 L of the solution to prepare a solution
having pH 12 at 25oC?
[3]
OR
0
0
a. Given EAl3+/Al = – 1.66V and EZn2+/Zn = - 0.76V
i. Calculate the standard emf of the cell and write the cell reaction.
[2]
ii. Construct the galvanic cell with Aluminium and Zinc as electrodes. [2]
iii. Draw energy profile diagram for exothermic and endothermic
reaction.
[2]
iv. Derive Gibb's Helmholtz equation.
[2]
10. a) An aliphatic compound (A) react with SOCl 2 to give (B).The compound (B) on
dehydrohalogenation yield (C). The compound (C) on ozonolysis gives a mixture
of ethanal and methanal. If the compound (A) is an alcohol and gives positive
iodoform test. Wtite the IUPAC name of A,B,C.
[3]
b) What product would you expect when benzaldehyde is heated with NaOH
solution?
[2]
c. Write one example of coupling reaction.
[1]
o
o
[2]
d. How can you test 1 amine from 2 amine? Write a reaction only.
11. A. How is propanone is prepared from
a. Propan-2-ol b. 2,2-dichloropropane c. Propyne
[3]
B. An organic compound C 5 H 10 O reacts with Phenylhydrazine to form phenyl
hydrazone. The compound gives Fehling’s solution test but does not give Iodoform
test. The compound on wolf-kishner reduction gives pentane. Identify the organic
compound giving the necessary chemical reactions. [5]
OR
Aniline gives electrophilic substitution reaction more readily than benzene.
a. Why is NH 2 group in aniline an ortho and para directing towards electrophilic
substitution reaction?
[2]
b. Starting from aniline how will you get sulphanilic acid, schiff’s base and carbolic
acid?
[3]
c. Explain why it is necessary to protect NH 2 group in aniline before nitration? [3]
Model Question- 10
Chemistry XII
Time :3 hours
Full marks: 75
Group 'A'
Circle the best alternative to the following questions. [11 × 1 = 11]
Time: 25 mins
1. A commercially available sample of H 2 SO 4 is 20% by mass (density = 1.1 g/l). The
molarity of the solution is
a. 2.24 M
b. 36 M
c. 3.6 M
2. According to Ostwald's dilution law,
156
d. 224 M
Ka
b. α2C = K a
c. K.V
d. all
C
3. For the reaction, N 2 O 5 (g) → 2NO 2 (g) + ½ O 2 (g), the value of the rate of disappearance
of N 2 O 5 is given as 6.5 × 10-2 mol L-1 s-1. The rate of formation of NO 2 is
a. α =
a. 3.25 × 10−2 mol L−1s−1
b. 1.3 × 10−1 mol L−1s−1
c. 1.3 × 10−2 mol L−1s−1
d. None of these
4. The cell notation for a reaction, Pb + 2Ag+
a. Ag / Ag+ // Pb 2+ / Pb
c. Pb / Pb2+ //Ag+ / Ag
5.
Pb2+ + 2Ag
b. Ag+/ Ag // Pb / Pb2+
d. Pb2+ / Pb // Ag / Ag+
Transition metals are complexes act as
a. Lewis acid
b. Lewis base
c. Neutral
d. none of the above
6. Impurities of sulphur, silicon and phosphorus can be removed from cast iron by adding
a. carbon which reduces the impurities
b. water which dissolves the impurities
c. limestone which changes impurities into oxides and pass into slag
d. iron oxide which reacts with impurities by forming slag
7.
Which of the following does not yield alkyl halide
a. Diethyl ether + RCOCl
b. Diethyl ether + PCl 5
c. Diethyl ether + HI
d. Diethyl ether + Cl 2
8. In organometallic compound, carbon is linked with metal by
a. ionic bond
b. Vander waal’s force
c. hydrogen bond
d. covalent bond
9. Which of the following is not primary raw materials for cement?
a. Limestone
b. Sand
c. Clay
d. gypsum
10. Main fibrous raw materials used in paper industry is
a. wood
b. grass
c. recycling paper d. sugarcane bagasse
11. Which of the following is the smallest particle of an element that retains the properties of
that element?
a. Isotope
b. Atom
c. Radioisotope d. None of these
Attempt all the questions:
Group 'B'
Short Answer Questions: [8×5=40]
1. a) What is redox titration. Which indicator do you use in the titration of oxalic acid
and potassium permanganate?
(1+1)
b) 25 cc of Na 2 CO 3 solution requires 28 cc of 1/10 N HCl for neutralization.
Calculate the strength of Na 2 CO 3 in terms of, normality, molarity, and g/l. [3]
OR
The following data were obtained at 300K for the reaction 2 M + N → product
157
Exp. No.
1
2
3
4
5
6
Calculate:
[M] (mol L-1)
0.10
0.30
0.30
0.30
0.60
0.10
[N] (mol L-1)
0.20
0.40
0.80
1.60
0.80
0.40
Rate of formation (mol L-1)
3 x 102
3.6 x103
1.44 x 104
A
B
C
a. Overall order of reaction
b. Calculate the value of A, B, and C
[1+4]
2. What happens when blue vitriol is heated at 100 °C? Write the anodic and cathodic
reactions occured during the rusting of iron according to the electrochemical theory of
rusting. Define the terms: i. coordination number ii. complex ion
[1+2+2]
3. What are volatile metals? How is steel manufactured by open hearth process? Explain
with well labelled diagram.
[1+4]
4. Define internal energy. The heat of formation of carbon dioxide, water and glucose
are -395, -269 and -1169KJ respectively. Calculate the heat of combustion of
glucose.
[1 + 4]
5. A primary alkyl halide (A) C 4 H 9 Br, reacted with alc. NaOH to give compound (B)
which when reacted with HBr give (C) which is an isomer of (A). When A was heated
with sodium, it gives compound (D) C 8 H 18 . (D) was different than the compound
produced when n-butyl bromide was reacted with sodium metal. Identify compound
(A). Write all concerned reactions.
[5]
OR
What happens when
i.
The product obtained by heating chlorobenzene with aqueous NaOH is allowed to
reacts with CO 2 at about 1250C under pressure?
[2]
ii. The product obtained by treating chlorobenzene with cuprous cyanide in the
presence of pyridine is hydrolyzed in the presence of dilute HCl.?
iii. Chlorobenzene is sulphonated?
[2]
[1]
6. An organic compound (A) C 2 H 6 O reacts with sodium to form a compound (B) with
evolution of H 2 gas and gives a yellow compound (C) when heated with I 2 and
0
NaOH. When (A) is heated with conc. H 2 SO 4 at 140 C it gives a compound (D)
C 4 H 10 O which on treatment with excess of conc. HI gives (E). (D) is also obtained
when (B) is heated with (E). Identify (A), (B), (C), (D) and (E) and write the reaction
involved.
158
7. Phenol can be identified in the laboratory by FeCl 3 test, bromine water test and
libermann test. Write reaction involve.
8. A. Distinguish between antibiotic and sulphadrugs. Define tranquilizer with
example?
[2+1]
B. Write one application of radioisotope in each of following:
a. Chemistry
b. Medicine
[1+1]
Group 'C'
[3 ×8=24]
Long Answer Questions
9. a) What is salt hydrolysis? Why is the aqueous solution of CuSO4 acidic? [1+2]
b) Define the degree of ionization of solution.The equal volume of two solutions
having pH =4 and pH =5 is mixed. Calculate the pH of the resulting
mixture.
(1+4)
OR
a). How is single electrode potential originated?
b). Predict which of the following reaction is spontaneous.
Given, Fe +1/ Fe+2 =0.77 V , Sn+4 / Sn +2 = +0.15V
i. 2Fe+2 + Sn +4 → 2Fe +3 + Sn +2
ii. 2Fe+3 + Sn +2 → 2Fe +2 + Sn +4
[1]
[3]
c) Define entropy. Predict in which entropy of the following increases or decreases
a.Liquid crystallize into solid
b. Temperature of crystallized solid is raised from 0K to 100K.
c. H 2 (g) → 2H (g)
. 10.
[1+3]
Identify the compounds A, B, C, D and E in the following sequence of reaction.
Cl 2 CH 3 Cl
O 2 /V 2 O 5 alcKCN
A
B
Anhy.AlCl 3
C
D
Na, dry ether
E
reflux
Compound (A) is an aromatic hydrocarbon.
(5)
ii) Convert benzaldehyde into Cinnamic acid.
(1.5)
iii) Give a chemical test to distinguish between benzaldehyde and formaldehyde.
(1.5)
11. Organic compounds can be distinguished by the suitable chemical test.
a. Suggest the suitable chemical test to distinguish ethanol from methanol.
b. Write the suitable chemical test to distinguish phenol from ethanol
c. Prepare the drug like aspirin which are used to relieve pain known as analgesics.
d. Prepare primary alcohol by ‘Oxo process’
[2+2+2+2]
OR
a. Explain why ethylamine is stronger base than ammonia.
159
[2]
b. Convert: aniline into p-sulphanilic acid
[2]
c. How would you obtain ethanoic acid from
i. malonic acid
ii. 1,1,1-trichloroethane iii Sodium methoxide
iv. Ethanol
[1+1+1+1]
160