ALL GOA CHEMISTRY TEACHER’S ASSOCIATION
MODEL QUESTION PAPER-VI (2023-2024)
STD: XII SCIENCE
NUMBER OF QUESTIONS: 35
SUBJECT: CHEMISTRY
No. OF PGS:04
MAXIMUM MARKS: 70
DURATION: 150 MINUTES
INSTRUCTIONS:
i) All questions are compulsory; however, Q. No 22, 31, 33, 34 and 35 have internal choice.
ii) Answer each question only once.
iii) Use of calculators is not permitted. Logarithmic tables will be provided on request.
iv) Question Nos. 1 to 13 carry one mark each.
(v) Question Nos. 14 to 25 carry two marks each.
(vi) Question Nos. 26 to 32 carry three marks each.
(vii) Question Nos. 33, 34 & 35 carry four marks each.
For Qs number 1-8,select the correct alternative from the ones given below and rewrite the
correct statement:
Q.1
Copper metal has a face centered cubic structure with the unit cell edge length of 360 pm. The
radius of copper atom is ______.
*1021.2 pm
*256 pm
*180 pm
1
*126.9 pm
Q.2
For the chemical reaction A + B
C + D , if the concentration of A is doubled without 1
altering that of B, rate of the reaction doubles. If the concentration of B is increased nine times
without altering that of A , the rate of the reaction triples. The order of the reaction is ______.
*3/2
*4/3
*2
*1
Q.3
In SN2 reaction, the correct order of reactivity of the compounds (CH3)2CHCl , CH3CH2Cl ,
CH3Cl and (CH3)3CCl is _________.
1
* (CH3)3CCl > (CH3)2CHCl > CH3CH2Cl > CH3Cl
* CH3Cl > CH3CH2Cl > (CH3)2CHCl > (CH3)3CCl
* CH3Cl > (CH3)2CHCl > CH3CH2Cl > (CH3)3CCl
* CH3CH2Cl > CH3Cl > (CH3)2CHCl > (CH3)3CCl
Q.4
The major product obtained when phenol is treated with chloroform and excess of aqueous alkali
is __________.
*2-Hydroxybenzaldehyde
* 4- Hydroxybenzaldehyde
*2- Hydroxybenzoic acid
* 4- Hydroxybenzoic acid
1
Q.5
The number of moles of KMnO4 that will be needed to react completely with one mole of KI in
acidic medium is __________.
*5/3
*1/5
* 2/5
* 3/5
1
Q.6
The solubility of gas in liquid increases with ___________.
*increase in temperature
*decrease of pressure
*decrease in temperature
* amount of liquid taken
Q.7
The correct order of basicity of the following amines in aq. solution is ______.
NH3
CH3CH2NH2 (CH3CH2 )2NH (CH3CH2 )3N
A
B
C
D
*C>D>B>A
Among the following a water soluble vitamin is _______.
*Vitamin A * Vitamin Bcomplex *Vitamin C * Vitamin D
Q.9 Draw a neat labelled diagram of froth floatation process.
Q.10 Cresols are less acidic than phenols. Give reason.
1
1
1
1
Q.8
*D > C > B> A * B > C > A > D
1
Page
*A > B > C > D
1
Q.11 Write the I.U.P.A.C name of the ionization isomer of [Co(NH3)5SO4]Br.
1
Q.12 What is shape selective catalysis?
Q.13 Mention two advantages of a fuel cell.
Q.14 Differentiate between Novolac and Bakelite on the basis of their structure and write labeled
equation to show the preparation of Nylon 6,6.
1
1
2
Q.15 Name two oxoacids of chlorine.
Arrange hydrogen halides in increasing order of their acidic strength.
2
Q.16 Name an artificial sweetener whose use is limited to cold foods only.
Which chemical substance is used as an antiseptic as well as a disinfectant?
To which class of drugs does chloramphenicol belong?.
State the class of detergents having germicidal properties.
Q.17 Draw a neat diagram of the Lead storage cell and label the anode, cathode and the electrolyte
used.
Q.18 A first order reaction takes 69.3 minutes for 50% completion. How much time will it take for
90% completion?
Q.19 Write chemical equations for the preparation of benzaldehyde by Rosenmund reduction and
Gatterman- Koch reaction respectively.
Q20 Mention two characteristics of interstitial compounds. Why is Actinoid contraction greater than
lanthanoid contraction?
Q.21 Identify compounds P and Q in the following sequence and write their structures and names
P NaBr +H2SO4 Alkyl halide containing
KNO2
Q
2
2 C atom
2
2
2
2
2
Major product
Q.22 Determine the value of ΔG⁰ and log Kc for the following
R (s)+ 2S + (aq)
R 2+ ((aq)) + 2 S(s) , having E⁰ cell = 0.59 V
-1
F = 96500 C mol
2
OR
Calculate the standard electrode potential of Ni 2+ /Ni electrode if the cell potential of the cell
Ni Ni 2+ (0.01M)
Cu2+ (0.1 M) Cu is 0.59 V
2+/
Given E⁰ Cu Cu = 0.34V
Q.23 Write electronic configuration of Europium (II) ion which is a strong reducing agent.
(Z of Eu = 63).
Ti(II) salts are coloured while Ti(IV) salts are colourless. Give reason.
2
Q.24 Draw the structure of the chiral compound ‘A’ having molecular formula C4H9Cl.. Compound A 2
when heated with alcoholic KOH forms a stable compound ‘B’. Compound ‘B’ when treated
with HBr forms compound ‘C’, which on further treatment with NaI forms compound ‘D’.
Identify compounds A,B,C and D.
Q.25 Derive Integrated rate equation for first order reaction.
2
Q.26 Radha and Seema during their educational tour visited the following places:
Aluminium extraction plant in Odisha and Bhaba atomic research centre Trombay unit where Si
and Ge are purified.
Name the process used for the electrolytic extraction of Al from alumina. What is the role of
cryolite in this process?
Name the process used for refining Si and Ge with high degree of purity. State the principle used
in this process.
Q.27 Draw a neat labeled diagram to illustrate electrophoresis.
Define mutual coagulation.
Distinguish between lyophilic and lyophobic colloids with respect to reversibility.
3
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2
3
Q.28 Differentiate between homoleptic and heteroleptic complexes.In the following complexes,
[NiCl4]2- and [Ni(CN)4]2- , State the hybridized state of Ni and their magnetic character.
3
Q.29 What is denaturation of proteins?
Write labelled equation to show the action of Br2 water on glucose.
Differentiate between DNA and RNA with respect to the sugar moiety present in them.
3
Q.30 In a face centred cubic lattice of A and B atoms. A atoms are present at the corners and B at the
face centres. If A atoms are missing from four corners in each unit. What is the simplest formula
of the compound?
Name the attractive forces which holds atoms or molecules of non polar and polar molecular
solids.
Draw diagram showing impurity defect when molten AgCl containing little amount of CdCl2 is
crystallised.
3
Q.31 An organic compound ‘A’ having molecular formula formula C4H8 on acid catalyzed hydration 3
forms compound ‘B’ as the major product . Compound ‘B’ on treatment with conc HCl and
anyh.ZnCl2 gives compound ‘C’, which on treatment with sodium ethoxide gives an isomer of
A as major product. Identify compounds A, B, C and write chemical equations for the above
sequence of reactions.
OR
3
Q.33 A solution was prepared by mixing 40 ml of a solute and 60 ml of solvent. It was observed that
the volume of the resultant solution was slightly less than 100 ml. Draw a graph to show the type
of deviation shown by this solution from Raoult’s law.
A solution of urea in water has a boiling point of 100.256 ⁰C. Calculate the freezing point of the
same solution. Given Kf and Kb are 1.86 ⁰C and 0.512 ⁰C respectively.
OR
Draw a graph showing depression of freezing point of solution when a non volatile solute is
added to it.
Calculate the osmotic pressure of a solution obtained by mixing 100 ml of 1.5% solution of urea
( molar mass =60) and 100 ml of 3.42% of sucrose( molar mass =342) at 298 K , R = 0.082 L
atm/degree/mol)
4
Q.34 Arrange the hydrides of group 15 elements in decreasing order of their basicity.
Draw the structure of xenon hexafluoride.
Write chemical equation to represent Deacon’s process.
Why do elements of group 16 have lower ionization enthalpy as compared to group 15 elements.
OR
Arrange the hydrides of group 17 elements in increasing order of their acidic character.
Draw the structure of phosphine.
Write chemical equation to show the action of sulphuric acid on sugar.
Why do noble gases have very low boiling points?.
4
Page
Q.32 Write chemical equation to convert benzamide to aniline.
p-Hydroxyazobenzene is an orange coloured dye. Write chemical equation for its preparation.
Aromatic primary amines cannot be prepared by Gabriel phthalimide reaction. Give reason.
3
Compound ‘X’ with molecular formula C9H12 when subjected to air oxidation followed by
hydrolysis gives compound ‘Y’ along with another compound Z, which gives positive iodoform
test. Compound X when oxidized with sodium dichromate in presence of sulphuric acid gives
benzoic acid. Identify compounds X, Y, Z and write chemical equations for the above sequence
of reactions.
Q.35 Write the sequence of reactions involved and name the compounds U,V, W and
4
X.
Aromatic acyl halide
having 7 carbon atoms
Pd-BaSO4
U
Zn-Hg +HCl
X
NH2OH
C6H5COCH3
OH- , 293K
V
W
OR
Write the sequence of reactions involved and name the compounds P,Q,R and S
Aromatic
hydrocarbon
containing 8
carbon atoms.
i. KMnO4 – KOH
ii. H3O
+
P
Q
i.NaOH
soda llime
Simplestii.aromatic
hydrocarbon
4
Conc H2SO4 + CONC HNO3
R
i. LiALH4
ii. H3O+
S
Q
4
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Q.35