SAMPLE PAPER - II

ClassXII

Chemistry

Time :3 Hrs. M.M. 70

General Instructions :

1. All questions are compulsory.

2. There is no overall choice in the questions paper, however internal choices are provided in

some questions.

3. Questions no. 1 to 8 are very short answer type questions and carry 1 mark each.

4. Question no. 9 to 18 are short answer type question and carry 2 marks each.

5. Question no. 19to 27 are short answer question of 3 marks each.

6. Question no. 28 to 30 are long answer question of 5 marks each.

7. use of log table is permitted.

1. A compound containing 2 atoms, X and Y crystallize in a cubic lattice with atoms X at the

corners of the unit cell and atoms Y at the body centers. Write the Formula of the

compound.

2. Why is ferric chloride preferred over Potassium chloride in case of a cut leading to

bleeding ?

3. What is the role of a depressant in the froth floatation process ?

4. Which will have higher B. pt. 0.1 M Nacl or 0.1 M baCl2 solutions in water ?

5. Predict the shape of Cl F3 on the basis of VSEPR theory.

6. Write the structure of 3-methyl pent-3-en-2-one.

7. K2PtCl6 is a well known compound while K2NiCl6

is not known . why ?

2

8. In the following pairs of organic compound identify the compound that will undergo SN1

reaction faster

Cl CH2Cl

9. The boiling point elevation of 0.6 g actic acid in 100 g of bengene is 0.1265 K. What

conclusion can you draw about the molecular state of the solute in solution ?

Kb for benzene is 2.53 degree per motal.

10. Consider the following reaction, 2NO(g) + 2H2 (g)

Rate = K [NO]2 [H ]

Propose a mechanism of this reaction.

N2(g) +2H2o (g)

11. Distinguish between the following pairs of compound with a siutable chemical

test

(a) Ethanol and phenol

(b) N-methylethanamine and ethanamine

12. Distinguish between any two of the following pairs

(a) Essential and non-essential amino acids

(b) ab

structure

(b) a-Helix and β-pleated sheet structure

(c) Amylose and amylopectin.

13. Account for the following

(a) Tertiary amines are weaker base than secondary amines in aqueous

solutions.

(b) Ketones are less reactive towards nucleophilic substitution reaction

than aldehydes.

2 4

14. The chioce of a reducing agent in a partcular case depends on

thermodynamic factor. How far do you agree with this statement ?

15. (a) Distinguish between ideal and non-ideal solutions.

(b) State Henery's law. 16. Explain the following name reaction

(a) Cannizaro reaction.

(b) (Reimer-Tiemann Reaction)

17. (a) Amino acids are amphoteric in nature. Why?

(b) What happens when glucose is treated with Br2 water.

OR

17. On electrolysis in acidic solutions amino acid migrate towards cathode while

in alkaline solution these these migrate towards anode. Explain.

18. What happens when ethanol is heated with conc. H SO at 140o

c ? Write the

mechanism of the rxn .

19. Write names of monomers of the following polymers and classify them as

homopolymer or copolymer

Buna S, Bakelite, teflon.

20. NaCl lattice has fcc structure. By X-ray diffraction, it is determined that the

distance between Na+

and Cl- ion is 282 pm.calculate the density of NaCl.

21. The activation energy of a first order reaction is 30 kJ/mol at 25o c.The

activation energy of the same same reaction in the presence of a catayst is

24kJ/mol at 25o

c How many times the rate of a reaction change in the

presence of a catayst at 25o c

2 2

2 6 4

22. (a) Explain the prepration of silver sol with a suitable diagram. Name the

method of preparation.

(b) What is meant by shape selective catalysis ? Name the catalyst used in

obtaining gasoline from alcohol.

23. (a) Write the structured formula of XeF2.

(b) Give reasons :

(i) Nitric oxide become brown . When released in air.

(ii) Of all nobel gases only xenon forms chemical compounds.

24. (a) Arrange HOCl , HOBr and HOI in increasing acid strength.

(b) Why does PCl5 fume in moisture ?

(c) Write only the reactions involved in the manufacture of HNO3 by

Oswtald's process.

25. (a) Write IUPAC name of [Co(en) Cl ]+

(b) Describe the type of Hyloridization, shape and magnetic properly of

[Fe(H O) ]2+

[OR] [Ni(CO )]

(Atomic number : Fe=26, Co= 27, Ni=28)

26. (a) Name a compound that acts as both antiseptic as well as disinfectant

(b) Why is bithional added to the toilet soap.

(c) What type of drug is chloramphenicol ?

27. An alkene (A) on ozonolysis yields acetone and an aldehyde. The aldehyde is

easily oxidized to an acid (B). When (B) is treated with Br2 in presence (C) of

phosphorus, if yields a compound C which on hydrolysis gives a hydroxy acid

(D) . This acid can also be obtained from acetone by the reaction with HCN

followed by hydrolysis. Identy the compound A to D giving suitable reasons

and relevant reactions.

. If

M

2 7

Or

An organic compound (A) with molecular formed C8H8 O forms an Orange- red

precipitate with 2,4-DNP reagent and gives yellow precipitate on heating with

iodine in the presence of sodium hydroxide. It neither reduces Tollen's or

Fehlings reagent nor, dos it decolorize bromine water or Baeyer's reagent.

On drastic oxidation with chromic acid , it gives a carboxylic acid (B) having

molecular formula C7H6O2. Identify the compounds (A) and (B) and explain

the reactions involved.

28. (a) consider cell,

Zn(s) I Zn2+(aq) (1.0M) II Cu2+(aq) (1.0 M) I Cu(s)

(i) Write the cell reaction

(ii) Calculate emf of the cell

(iii) Is the cell reaction spontaneous or not

Given : E°Zn2+/Zn

= –0.76V E°Cu2+/Cu = 0.34V

(b) Predict the products of electrolysis in each of the following

(i) An aqueous solution of AgNo3 using silver electrodes.

(ii) An aqueous solution of CuCl2 using platinum electrodes.

Or

28. (a) Resistance of a conducting cell filled with 0.1 MKcl solutions is 100

the resistance of the same cell when filled with 0.02 M kCl solution is 520

calculate the conductivity

and molor conductivity of 0.02

KCl

solution. Conductivity of 0.1 M KCl solution id 1.29 S m-1.

(b) State two advantages of H2-O2 fuel cell over ordinary cell.

29. (a) What is lanthanoid contraction ? What is its effect on the chemistry of the

elements which follow the lanthanides ?

(b) What happens when Cr O 2-

reacts with Fe 2+

in acidic medium ? Write

relevant balanced equation.

(c) Cu+ salts are colorless while Cu

2+ salts are colored. why ?

(d) Calculate magnetic moments of a divalent ion in aqueous solution if its

atomic number is 25.

Or

(a) How would you account for the following :

(i) The transition elements have high enthapies of atomisation.

(ii) The transition metals and their compounds act as good catalysts

in many processes.

(b) Black solid (A) reacts with KOH Or K2 CO3 in presence of air o give (B)

which forms green solutions. when Cl2

gas is passed through green

solutions, the colour of solution changes to purple due to formation of C.

identify A,B,C and write chemical equations.

30. (a) Write IUPAC name of OH O

CH3-CH-CH2-C--H

(b) Convert benayl alcohol to phenyl etahnoic acid

(c) Which of the following compounds would under go aldol condensation,.

Which cannizaro reaction and which neither ? give reason.

Methanal, 2- methyl pentanal,

butan 1-ol

OR

(a) Arrange CH3 CH2 CH (Br) COOH, CH3 CH (Br) CH2 COOH

(CH3)2

CH COOH, CH3

CH2

CH2

COOH increasing order of acid

strength.

(b) Convert Ethanol to 3-Hydroxy Butanol

(c) Give reasons

(i) Boiling points of aldehydes & ketones are lower than that of

corresponding acids

(ii) CHCl3 should be stored in dark brown colored bottle.

(iii) CHCl3 is a chlorine compound but it does not give white precipitate

with silver nitrate solution

9.

Sample paper 2

ClassXII

Marking Scheme Chemistry

Time :3 Hrs. M.M. 70

1. X= 8 x 1/8 =1 Y=1

Formula =XY

2. Because fe

3+ has a highercharge than k

+ and thus has more coagulating power 1

3. They prevent certain particales from forming the from 1

4. 0.1 M BaCl2 1

5. T-shaped 1

6. CH3– C–C =CH-CH3 1

O CH3

7. AS sum of first four IE is less in Pt than in Ni

8. CH2 CI

∆Tb = Kb.Mi

∆Tb = Kb

MB= Kb X

WB X 1000 ½

MB X WA

WB X 1000

ΔTb X WA

=2.53 x 0.6 x 1000

= 120

0.1265x 100 ½

11. (a) Iodoform test or neutral FeCl3 test or any other

(b) Hinsberg test.

17. (a) Correct reason

(b) Correct reaction

I = Normal molecular mass

Observed molecular mass

60 =

120=

0.5 ½

: I= 0.5, solute exists as a dimer in solution ½

10. 2 NO(g)+ H2(g) slow N2(g) +H2O2

H2O2+H2(g) fast 2H2O(g)

1+1

12. I mark for each correct difference 1

13. (a) Correct reason 1

(b)

Correct reason 1

14. Correct reason 1

15. (a) Correct differences (any 2) 1

(b) Correct statements 1

16. Correct reactions 1+1

1

OR

Correct explanation wrt acidic and alkaline solution each

18. 2C2 H5 OH

conc. H2SO4

140°C

C2 H5 O C2 H5 1

H

CH3 CH2–ÅO–H

CH3–CH2–O–H H+

CH3 CH2 O CH2

CH3

-H+

– H2O CH3CH2OH

CH3–CH2–O–CH2CH3

+ H

= 2.16A5 gX/cNm a

2

0

3

2

1

K

19. Buna S Copolymer Bultadiene & Styrene

Bakelete Copolymer Phenol & Formaldehyde

Tefflon Homopolymer Tetrafluoroethene

(½) mark for each correct answer

20. Z= 4 Fec structure 1/2

a= 2 x 282 = .564 Pm 1/2

d = (1/2+1/2)

Z x M = 4 X 58.5

3 (564)

3 x 10

-10 x 6.023 x 10

23 1

21. log K

K =

Ea - Ea (c) 1/2

2.303 RT

(30000-24000)

2.303 x 8.314 x 298

= 1.0516 K2

= antilog (1.0516) 1

K2 = 11.27 K1

22. (a) Proper explanation of Bredig's Arc method along with its diagram 1½

(b) Explanation of selective catalysis ZSM -5 1

23. (a) F 1

XE

(b) (i) F Due to its formation of NO 1

(ii) Due to its comparable ionization energy with oxygen

24. (a) HOI, HOBr, HOCL 1

(b) Due to formation of HCl 1

(c)

4HN3+(g)5O2(g)

2NO(g)+O2(g)

Pt

500 K,9 bar

4NO(g)+6H2O(g)

2NO2(g)

25. (a) Dichlorido bis (ethane-1, 2,- diamine) cobatt (III) ion 1

3NO2(g)+H2O(l) 2HNO3(g)+ NO(g)

2 6

4

+

(b) [Fe(H 0) ]2+

Hybridization – Sp3d

2 A

Shape–Octahedral (2)

Magnetic property –paramagnetic

OR

[NI(CO) ] Hybridization–Sp3

Shape –Tetrahedral

Magnetic Property – Diamagnetic

26. (a) Phenol 1

(b) To impart antiseptic properties 1

(c) Broad spectrum antibiotic 1

27.

A + O3 CH3C CH3 + Aldehyde

Aldehyde [o]

acid (B)

B+Br2 P (C) H2O

Hydroxy acid (D)

CN

O OH H2O H COOH

CH3–C–CH3

(OD)H

A– 1/2 CH3–CH–CH=C–CH3

CH3 CH3

CooH B– CH

3 – CH – CH

3

1/2

CooH C– CH3 – C – CH3

Br

D– CooH

1 mark for explanatioN

1/2

CH3 – C – CH3

OH

l

2+

COCH3

Cl

NO2

+ H2 N. HN NO2

(A) H2O NO2

H3C C N NH NO2

COOH

H2 CrO4

COCH3

NaOH

I2

COONA

+

CHI3

(B) (A)

Zn(s) + Cu2+(ag) Zn (ag) + Cu(s)

Cell const K =

R -1

129 m -1 =

520

= 248 Sm ---------1

= 0.248 ́10 -1 S cm -1

129m λ=

C

=124 S cm 2 mol-1

2- 2+ +

6 5 2

+

-

CR2 07 +6FE +14 H 2 Cr3++ 6Fe3+ + 7H2O

µ= 5 (5+ 2) =35 BM

C6 H5 CH2

OH

HBr C H CH Br K CN

C6 H5 CH2 CN

28. (a) (i)

(ii) 1.10 v

(iii) Reaction is spontaneous

H2O |H 1

C6 H5 CH2 COOH 1

(b) (i) Cathode : Ag sets deposit 1

Ag++e

- Ag

Anode Ag e- + Ag

+

(ii) Cathode : CU2+2

e-

Anode : Cl-

½

CU

E + Cl

Pcc Cl+Cl Cl2

Or

NaOH ½ Aldol Condensation

-1 -1

(a) Cell constant = K x R = 1.29 x 100 = 129 m = 1.29 cm 3

CH3–CH–CH2–CHO

OH

(b) 2 Advantage (1+1)

29. (a) Correct answer 2

(b) 1