NAVODAYA VIDYALAYA SAMITI (SHILLONG REGION)
Practice Paper Set-1
SUBJECT: CHEMISTRY (043)
CLASS- XII
TIME: 03:00 hrs MM:70
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 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 question
carries 1 mark. There is no internal choice in this section.
1 Which of the following statements is not correct? 1
(a) La(OH)3 is less basic than Lu(OH)3
(b) La is actually an element of transition series rather than Lanthanoids
(c) Atomic radius of Zr and Hf is same
(d) In Lanthanoid series, the ionic radius of Lu3+ is smallest
2 The formula of the complex tris(ethan-1,2 diamine)cobalt(III) Sulphate is 1
(a)[Co(en)3]SO4 (b)[Co(en)3 SO4]
(c)[Co(en)3]2(SO4)3 (d)[Co(en)3](SO4)3
3 The compounds [Cr(NO2)(NH3)5]Br and [Cr(ONO)(NH3)5]Br represents 1
(a) Linkage isomerism (b) No isomerism
(c) Ionisation isomerism (d) Coordination isomerism
4 Which of the following compounds on treatment with benzene sulphonyl chloride forms an 1
alkali soluble precipitate?
(a) (CH3)3N (b) CH3CONH2 (c) (CH3)2NH (d) CH3CH2NH2
5 For Na2SO4 the value of Van’t Hoff factor is 1
(a) 0 ( b) 1 (c) >1 (d) <1
6 Which glycosidic linkage is present in maltose? 1
(a) α -D – (+) - Glucose (C1 ) – O – (C2 ) - β - D- (-) – glucose
(b) β -D – (+) - Glucose (C1 ) – O – (C4 ) – β- D- (+) – glucose
(c) α -D – (+) - Glucose (C1 ) – O – (C4 ) - α -D- (+) – glucose
(d) β -D – (+) - Glucose (C1 ) – O – (C4) - α - D- (-) – glucose
7 The ionic conductance of Ba2+ and Cl- ions are respectively 127 and 76 Ω-1 cm2 at infinite 1
dilution. The equivalent conductance of BaCl2 at infinite dilution is
(a) 203 Ω-1 cm2 (b) 279 Ω-1 cm2 (c) 101.5 Ω-1 cm2 (d) 139.5 Ω-1 cm2
3
,8 In the plot of lnk vs 1/T,the slope is- 1
(a) -Ea (b) Ea/R
(c)Ea/2.303R (d)-Ea/R
9 Chlorobenzene is formed by reaction of chlorine with benzene in the presence of AlCl3. Which 1
of the following species attacks the benzene ring in this reaction ?
(a) Cl– (b) Cl+ (c) AlCl3 (d) [AlCl4]-
10 The pKa of phenol is lower than that of ____________ which is a _______ acid than phenol. 1
(a)ethanol, weaker
(b)o-cresol, stronger
(c)m-nitrophenol, weaker
(d)p-nitrophenol, stronger
11 Which out of the following reactions needs no α-H atom to get started? 1
(a) Etard reaction (b) Cannizaro’s reaction
(c) Aldol condensation (d) HVZ reaction
12 Which of the following pair of graphs represents the same order of reaction? 1
In the Following questions a statement of Assertion(A) is followed by a statement of Reason(R).
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.
13 Assertion (A):Sucrose is a non-reducing sugar. 1
Reason (R):In sucrose, the aldehydic group of glucose and ketonic group of fructose are
not free.
14 Assertion (A): Transition metals show variable valency. 1
Reason (R): Transition metals have a large energy difference between ns and (n-1)d
electrons.
4
,15 Assertion (A): Aromatic 1o amine can be prepared by Gabriel phthalamide synthesis. 1
Reason (R): Primary Alkyl halide undergoes nucleophilic substitution reaction with anion
formed by phthalamide.
16 Assertion (A): Nitration of aniline can be conventionally done by protecting the amino 1
group by acetylation.
Reason (R):Acetylation increases the electron density in benzene ring.
SECTION B
This section contains 5 questions with internal choice in one question. The following questions
are very short answer type and carry 02 marks each.
17 Calculate the mass of ascorbic acid (vitamin C , C6H8O6) to be dissolved in 75 g of acetic 2
acid to lower its freezing point by 1·5°C. ( Kf for CH3COOH = 3·9 K kg mol-1)
18 Calculate the emf of the cell given below at STP: 2
19 A metal ion M+ having d4 valence electronic configuration combines with three bidentate
ligands to form a complex compound. Assuming Δ 0> P: 2
(a)Name the type of orbital splitting during this complex formation. (1 mark)
(b)Write the electronic configuration of the valence electrons of the metal M + ion in terms of
t2g and eg. (1 mark)
20 Arrange the following sets of compounds in order of their increasing boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol. (1 mark) 2
(b) Pentan-1-ol, n-butane, pentanal, ethoxyethane.(1 mark)
OR
Explain the mechanism of the acid catalysed hydration of ethene.(2 marks)
21 What happens when D-glucose is treated with the following reagents? (1x2=2 marks) 2
(a) HCN (b)Br2/H2O
SECTION C
This section contains 7 questions with internal choices in one question. The following questions are
short answer types and carry 3 marks each.
5
, 22 (a)The limiting molar conductivity of sodium acetate, sodium chloride and hydrochloric 3
acid
◦
are 83, 127 and 426 mho 𝑐𝑚2 𝑚𝑜𝑙𝑙-1 at 250 𝐶 respectively. Calculate the limiting molar
conductivity of acetic acid solution.(2 marks)
(b)How
How many electrons flow through a metallic wire if a current of 0·5 A is passed for 2
hours? (Given : 1 F = 96,500 C mol−1−
) (1 mark)
23 The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain
Expl 3
the reactions occurring during the corrosion of iron in the atmosphere.
24 (a)Identify A to D 2
1
(b)convert Ethanoic acid to 2-hydroxyethanoic
hydroxyethanoic acid in not more than two steps.
25 (a)There are two solutions ‘A’ & ‘B’.One which is yellow(A) & another one which is 1+1
Green(B). The solutions are [Fe(H2O)6]+2 & [Fe(CN)6]-4. Among these which one is ‘A’ &
which one is ‘B’ ?Give
Give reason of your answer.
(b)Among [CoF6]-3 & [Co(C2O4]-3 Which one is more stable & why?
1
26 (a) 3
(iii)
OR
Write Short notes on the following reactions
(a) Williamson Synthesis
(b)Reimer Tiemann reaction
(c)Oxidation of phenol
27 Arrange the following: 3
(a)CH3NH2, (CH3)2NH, NH3, (CH3)3N [basic strength in gaseous phase] (In decreasing
order)
(b)C2H5NH2, C6H5NH2, NH3, (C2H5)2NH [solubility in water] ] (In increasing order)
(c)C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2 [pkb value] ] (In increasing
order)
28 Give answer for the following: 3
(a)The penta acetate of glucose does not react with Hydroxylamine.What does it indi
indicate?
(b)Define peptide bond.
(c)Why two strands of DNA are not identical rather they are complementary to each other?
Practice Paper Set-1
SUBJECT: CHEMISTRY (043)
CLASS- XII
TIME: 03:00 hrs MM:70
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 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 question
carries 1 mark. There is no internal choice in this section.
1 Which of the following statements is not correct? 1
(a) La(OH)3 is less basic than Lu(OH)3
(b) La is actually an element of transition series rather than Lanthanoids
(c) Atomic radius of Zr and Hf is same
(d) In Lanthanoid series, the ionic radius of Lu3+ is smallest
2 The formula of the complex tris(ethan-1,2 diamine)cobalt(III) Sulphate is 1
(a)[Co(en)3]SO4 (b)[Co(en)3 SO4]
(c)[Co(en)3]2(SO4)3 (d)[Co(en)3](SO4)3
3 The compounds [Cr(NO2)(NH3)5]Br and [Cr(ONO)(NH3)5]Br represents 1
(a) Linkage isomerism (b) No isomerism
(c) Ionisation isomerism (d) Coordination isomerism
4 Which of the following compounds on treatment with benzene sulphonyl chloride forms an 1
alkali soluble precipitate?
(a) (CH3)3N (b) CH3CONH2 (c) (CH3)2NH (d) CH3CH2NH2
5 For Na2SO4 the value of Van’t Hoff factor is 1
(a) 0 ( b) 1 (c) >1 (d) <1
6 Which glycosidic linkage is present in maltose? 1
(a) α -D – (+) - Glucose (C1 ) – O – (C2 ) - β - D- (-) – glucose
(b) β -D – (+) - Glucose (C1 ) – O – (C4 ) – β- D- (+) – glucose
(c) α -D – (+) - Glucose (C1 ) – O – (C4 ) - α -D- (+) – glucose
(d) β -D – (+) - Glucose (C1 ) – O – (C4) - α - D- (-) – glucose
7 The ionic conductance of Ba2+ and Cl- ions are respectively 127 and 76 Ω-1 cm2 at infinite 1
dilution. The equivalent conductance of BaCl2 at infinite dilution is
(a) 203 Ω-1 cm2 (b) 279 Ω-1 cm2 (c) 101.5 Ω-1 cm2 (d) 139.5 Ω-1 cm2
3
,8 In the plot of lnk vs 1/T,the slope is- 1
(a) -Ea (b) Ea/R
(c)Ea/2.303R (d)-Ea/R
9 Chlorobenzene is formed by reaction of chlorine with benzene in the presence of AlCl3. Which 1
of the following species attacks the benzene ring in this reaction ?
(a) Cl– (b) Cl+ (c) AlCl3 (d) [AlCl4]-
10 The pKa of phenol is lower than that of ____________ which is a _______ acid than phenol. 1
(a)ethanol, weaker
(b)o-cresol, stronger
(c)m-nitrophenol, weaker
(d)p-nitrophenol, stronger
11 Which out of the following reactions needs no α-H atom to get started? 1
(a) Etard reaction (b) Cannizaro’s reaction
(c) Aldol condensation (d) HVZ reaction
12 Which of the following pair of graphs represents the same order of reaction? 1
In the Following questions a statement of Assertion(A) is followed by a statement of Reason(R).
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.
13 Assertion (A):Sucrose is a non-reducing sugar. 1
Reason (R):In sucrose, the aldehydic group of glucose and ketonic group of fructose are
not free.
14 Assertion (A): Transition metals show variable valency. 1
Reason (R): Transition metals have a large energy difference between ns and (n-1)d
electrons.
4
,15 Assertion (A): Aromatic 1o amine can be prepared by Gabriel phthalamide synthesis. 1
Reason (R): Primary Alkyl halide undergoes nucleophilic substitution reaction with anion
formed by phthalamide.
16 Assertion (A): Nitration of aniline can be conventionally done by protecting the amino 1
group by acetylation.
Reason (R):Acetylation increases the electron density in benzene ring.
SECTION B
This section contains 5 questions with internal choice in one question. The following questions
are very short answer type and carry 02 marks each.
17 Calculate the mass of ascorbic acid (vitamin C , C6H8O6) to be dissolved in 75 g of acetic 2
acid to lower its freezing point by 1·5°C. ( Kf for CH3COOH = 3·9 K kg mol-1)
18 Calculate the emf of the cell given below at STP: 2
19 A metal ion M+ having d4 valence electronic configuration combines with three bidentate
ligands to form a complex compound. Assuming Δ 0> P: 2
(a)Name the type of orbital splitting during this complex formation. (1 mark)
(b)Write the electronic configuration of the valence electrons of the metal M + ion in terms of
t2g and eg. (1 mark)
20 Arrange the following sets of compounds in order of their increasing boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol. (1 mark) 2
(b) Pentan-1-ol, n-butane, pentanal, ethoxyethane.(1 mark)
OR
Explain the mechanism of the acid catalysed hydration of ethene.(2 marks)
21 What happens when D-glucose is treated with the following reagents? (1x2=2 marks) 2
(a) HCN (b)Br2/H2O
SECTION C
This section contains 7 questions with internal choices in one question. The following questions are
short answer types and carry 3 marks each.
5
, 22 (a)The limiting molar conductivity of sodium acetate, sodium chloride and hydrochloric 3
acid
◦
are 83, 127 and 426 mho 𝑐𝑚2 𝑚𝑜𝑙𝑙-1 at 250 𝐶 respectively. Calculate the limiting molar
conductivity of acetic acid solution.(2 marks)
(b)How
How many electrons flow through a metallic wire if a current of 0·5 A is passed for 2
hours? (Given : 1 F = 96,500 C mol−1−
) (1 mark)
23 The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain
Expl 3
the reactions occurring during the corrosion of iron in the atmosphere.
24 (a)Identify A to D 2
1
(b)convert Ethanoic acid to 2-hydroxyethanoic
hydroxyethanoic acid in not more than two steps.
25 (a)There are two solutions ‘A’ & ‘B’.One which is yellow(A) & another one which is 1+1
Green(B). The solutions are [Fe(H2O)6]+2 & [Fe(CN)6]-4. Among these which one is ‘A’ &
which one is ‘B’ ?Give
Give reason of your answer.
(b)Among [CoF6]-3 & [Co(C2O4]-3 Which one is more stable & why?
1
26 (a) 3
(iii)
OR
Write Short notes on the following reactions
(a) Williamson Synthesis
(b)Reimer Tiemann reaction
(c)Oxidation of phenol
27 Arrange the following: 3
(a)CH3NH2, (CH3)2NH, NH3, (CH3)3N [basic strength in gaseous phase] (In decreasing
order)
(b)C2H5NH2, C6H5NH2, NH3, (C2H5)2NH [solubility in water] ] (In increasing order)
(c)C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2 [pkb value] ] (In increasing
order)
28 Give answer for the following: 3
(a)The penta acetate of glucose does not react with Hydroxylamine.What does it indi
indicate?
(b)Define peptide bond.
(c)Why two strands of DNA are not identical rather they are complementary to each other?
