Sample
Paper-2
CHEMISTRY
Class:- XII
Max. Marks:-70
Subject:-
Chemistry Theory (043)
Max. 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 cases - 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.
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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. |
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Q
1. |
When
a lead storage battery is charged, then (a)H2SO4 regenerates (b)
PbSO4
get
deposited on lead electrode (c)
PbSO4
dissolves (d) Quantity of acid reduces |
1 |
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Q
2. |
The
best reagent for converting 2-phenylpropanamide into 2-phenylpropanamine is: (a) Br2 in aqueous NaOH (b)
LiAlH4 (c) iodine in the presence of red
phosphorus (d)
excess H2 |
1 |
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Q
3. |
The
slope in the plot of log [R]0/[R]vs time for a first
order reaction is : (a) +k/
2.303 (b) + k (c) -k/ 2.303 (d) – k |
1 |
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Q
4. |
In
the reaction, AÃ B the rate of reaction
increases two times on increasing the concentration of A four times, the
order of reaction is: (a)
2 (b) 0 (c) 1/2 (d) 3 |
1 |
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Q
5. |
Which
of the following is likely to form white salts? (a)
Cu2+ (b) Ti3+ (c) Fe3+ (d) Sc3+ |
1 |
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Q
6. |
Actinoids
exhibit a greater number of oxidation states than lanthanoids. The main reason
being: (a)
More
energy difference between 5f and 6d than between 4f and 5d –orbitals. (b)
4f-orbitals
are more diffused than the 5f-orbitals. (c)
Lesser
energy difference between 5f and 6d than between 4f and 5d –orbitals. (d)
More
reactive nature of the actinoids than the lanthanoids. |
1 |
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Q7. |
Aryl
halides cannot be prepared by the reaction of aryl phenols with PCl3,
PCl5 or SOCl2 because : (a)
Phenols are highly unstable compounds. (b)
carbon-oxygen bond in phenols has a partial double bond character. (c)
carbon-oxygen bond is non- polar (d) all of these |
1 |
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Q8. |
Which
of the following sugar is known as dextrose? (a)
Sucrose (b) Fructose (c) Ribose (d) Glucose (b)
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1 |
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Q9. |
The
correct IUPAC name of (CH3)2- C(OH) – CH2-
CH3 is: (a)
tert-butyl alcohol
(b)
2-Methylbutan-2-ol (c)2,2-
Dimethylbutan-3-ol (d)
3-Methylbutal-3-ol |
1 |
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Q10. |
Which
of the following compound will reacts with NaOH solution in water? (a)
C6H5OH (b) C6H5CH2OH (c) (CH3)3COH (d) C2H5OH |
1 |
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Q11. |
Which
of the following is most reactive in nucleophilic addition reaction? (a)
C6H5CHO (b) CH3- CO- CH3 (c) CH3CHO (d) HCHO |
1 |
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Q12. |
The
reagent which does not react with both, acetone and benzaldehyde is: (a)
Sodium
hydrogensulphite (b) Phenyl
hydrazine (c)Fehling’s solution (d)
Grignard reagent |
1 |
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Q13. |
Carboxylic
acid group doesn’t give the usual addition reactions of aldehydes
& ketones because (a) O-H
bond is more polar than C=O group. (b)
Carboxylate ion gets ionized. (c)
Carboxylate ion gets stabilized by resonance. (d)
It exists as –COOH & there is no carbonyl group. |
1 |
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Q14. |
Given
below are two statements labelled as Assertion (A) and Reason (R) Assertion
(A): Adenine
and Guanine are the purines present in both nucleic acids. Reason
(R): Thiamine
and Uracil are the pyrimidine present in DNA. 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 |
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Q15. |
Given
below are two statements labelled as Assertion (A) and Reason (R) Assertion
(A): Phenol
is more acidic than ethanol. Reason
(R): Phenoxide
ion is stabilized by resonance but ethoxide ion is not. 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 |
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Q16. |
Given
below are two statements labelled as Assertion (A) and Reason (R) Assertion
(A): An
electrochemical cell stops working when Ecell becomes zero. Reason
(R): E0cell
of an electrochemical cell never becomes zero. 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 |
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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. |
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Q17. |
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=1.86Kkg/mol) |
2 |
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Q18. |
Write
two differences between order of reaction and molecularity of reaction. |
2 |
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Q19. |
Give the reasons for the
following: (a)
Chloroethane
is insoluble in water. (b)
Thionyl
chloride method is preferred for the preparing alkyl chlorides from alcohols. |
2 |
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Q20. |
Write
the chemical equation involved in the following reactions: (a) Aldol Condensation (b) Cannizzaro reaction OR Give
chemical tests to distinguish between the following pairs of compounds : (a)
Phenol and Benzoic acid (b)
Acetophenone and Benzophenone |
2 |
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Q21. |
(a) What
are the nitrogenous base present in DNA and RNA? (b) Name the vitamin responsible for the
coagulation of blood. |
2 |
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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. |
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Q22. |
(a) State Kohlrausch’s law of independent
migration of ions. (b)
The conductivity of 0.20M KCl solution at 298K is 0.025 S cm-1.
Calculate its molar conductivity. |
3 |
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Q23. |
A
first order reaction takes 20 minutes for 25% decomposition. Calculate the
time when 75% of the reaction will be completed. (Given: log 2= 0.3010, log 3= 0.4771, log
4= 0.6020) |
3 |
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Q24. |
(a)Write
IUPAC name of [Cr (NH3)3 (H2O)3]
Cl3complex compound. (b)Describe
the shape and magnetic behaviour of following complexes: (i) [Co(NH3)6]3+ (ii) [Ni(CN)4]2- (At.No. Co = 27, Ni = 28) OR (a)
On
the basis of crystal field theory, write the electronic configuration of d4
in terms of t2g and eg in an octahedral field
when Δo> P. (b)
Draw
figure to show the splitting of d-orbitals in an octahedral crystal field. |
3 |
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Q25. |
The
following compounds are given to you: 2- Bromopentane, 2- Bromo-2-methylbutane,
1- Bromopentane (a)
Write
the compound which is most reactive towards SN2 reaction. (b)
Write
the compound which is optically active. (c)
Write
the compound which is most reactive towards β- elimination reaction. |
3 |
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Q26. |
Write
the mechanism of acid catalyzed dehydration of ethanol to yield ethene at 443
K |
3 |
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Q27. |
Convert the following: (a)
Benzoic acid to Benzaldehyde (b)
Ethyl
benzene to Benzoic acid (c)
Propanone
to Propene |
3 |
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Q28. |
What
happens when D-glucose is treated with. the following reagents? (a)
HI (b)
Bromine water (c) HNO3 |
3 |
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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. |
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Q29. |
In
coordination compound metal show two types of linkages- primary and
secondary. Primary valencies are ionisable are satisfied by negatively
charged ions .Secondary valencies are non- ionisable and are satisfied by
neutral or negative ions having lonepair of electrons. Primary valencies are
non-directional while secondary valencies decide the shape of the complexes. (a) IfPtCl2.2NH3 does not
react with AgNO3 , what will be its formula. (b) What is the secondary valency of [Co (en)3]3+? Note:- The option is available
below in part (c) only. (c)
(i)
Write the formula of Iron [III] hexacyanidoferrate[II] (ii)Write
IUPAC name of [Co(NH3)5Cl] Cl2. OR Write
the hybridisation and magnetic behaviour of [Ni(CO)4] [Atomic
number; Ni = 28] |
4 |
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Q30. |
Observe
the following table in which conductivity and molar conductivity of NaCl at
298K at different concentration & á´§m0 for different
electrolytes are given. Answer the questions based in the table that follows-
(1+1+2)
á´§m0 for NaCl = 126.4 S.cm2/mol HCl = 426.1 S.cm2/mol,CH3COONa=
91.5 S.cm2/mol,NH4Cl= 129.8 S.cm2/mol (a)
What
is the change in number of ions per unit volume with decrease in
concentration? (b)
Molar
conductivity decreases with increase in concentration as shown in table. Why?
Note:- The option is available below
in part (c) only. (c)
Find
out the limiting molar conductivity of CH3COOH from the values
given.
OR Conductivity
and molar conductivity varies differently with change in concentration. Justify. |
4 |
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SECTION E The
following questions are long answer type and carry 5 marks each. All
questions have an internal choice. |
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Q31. |
(a)
Define
the following terms: (i) Azeotropes (ii)Osmotic pressure (b)
Two elements
A and B form compounds having formula AB2andAB4.Whendissolved
in 20 g of benzene (C6H6), 1 g of AB2 lowers
the freezing point by 2.3 K whereas 1 g of AB4 lowers it by
1.3 K. The molar depression constantfor benzene is 5.1
Kkg/mol. Calculate atomic masses of A and B.
OR (a) Define
the following terms: (i) Anoxia (ii) Reverse osmosis (b) The
vapour pressure of pure benzene at a certain temperature is 0.850 bar.
A non-volatile, non-electrolyte solid weighing 0.5 g when added to 39.0
g of benzene (molar mass 78 g/ mol). Vapour pressure of the solution, then,
is 0.845 bar. What is the molar mass of the solid substance? |
5 |
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Q32. |
(a)
Give
the reason for the following: (Attempt any three of the following) (i)
Transition metal shows variable oxidation state. (ii)
Transition metals have tendency to form complex. (iii) Cu+ is unstable in aqueous
solution. (iv)
Study the chemistry of actinoids are complicated. (v)
Zn, Cd, Hg are not regarded as transition metal. Note:- The option is
available below in part (b) only. (b)
Write the equation involved in the preparation of potassium dichromate from chromite
ore. OR Write the equation involved in the
preparation of potassium permanganate from pyrolusite ore. |
5 |
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Q33. |
(a)
Account
for the following: (i)Aniline does not undergo Friedel crafts reaction.
(ii)Gabriel Phthalimide synthesis is
preferred for Primary amine. (b)
Arrange
the following in: (i)
decreasing order of the pKb values: C2H5NH2,
C2H5NHCH3, (C2H5)2NH,
and C6H5NH2 (ii)
decreasing order of the basic strength in gas phase. C2H5NH2,(C2H5)2NH
,(C2H5)3N ,NH3 (iii)
increasing order of solubility in water: C6H5NH2, (C2H5)2NH,
C2H5NH2 OR (a)
Account
for the following: (i)
Ethylamine is soluble in water whereas aniline is insoluble. (ii) Diazonium salt of aromatic amine are
more stable than aliphatic amine. (b)
An
organic compound 'A' having molecular formula C3H5N on
hydrolysis give another compound 'B'. The compound 'B' on treatment with HNO₂ gave ethyl alcohol. 'B' on warming with CHCl3
and alcoholic caustic potash gave an offensive smelling substance 'C'.
Identify A, B & C and write the reactions involved. |
5 |
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