CBSE Class 11 Chemistry Sample Paper

General Instructions:

a) There are 33 questions in this question paper. All questions are compulsory.

b) Section A: Q. No. 1 to 16 are objective type questions. Q. No. and 2 are passage based questions carrying 4 marks each while Q. No. 3 to 16 carry I mark each e) Section B: ( No. 17 to 25 are short answer questions and carry 2 marks each.

d) Section C: O No. 26 to 30 are short answer questions and carry 3 marks each.

e) Section D: Q No. 31 to 33 are long answer questions carrying 5 marks each.

There is no overall choice. However, internal choices have been provided Use of calculators and log tables is not permitted

SECTION – A (OBJECTIVE TYPE)

1- Read the following passage and answer the following questions of multiple choice:

The dynamic nature of chemical equilibrium can be demonstrated in the synthesis of ammonia by Haber’s process. In a series of experiments. Haber started with known amounts of dinitrogen and dihydrogen maintained at high temperature and pressure and at regular intervals determined the amount of ammonia present. He was also successful in determining the concentration of unreacted dinitrogen and dihydrogen

i) Name the catalyst used in the synthesis of ammonia.

(a) Platinum

(b) Silver

(d) Nickel

ii) Optimum temperature for the synthesis of ammonia using catalyst is:

(a) 500 C

(b) 200 C

iii) Optimum pressure for the syntiente ammonia using catalyst is :-

(a) 500 atm

(b) 200 atm

iv) Formation of ammonia is

(a) exothermic

(b) endothermic

(d) none of these

2- Read the following passage and answer the following questions of multiple choice:- Disproportionation reactions are a special type of redox reactions. In a disproportionation reaction an element in one oxidation state is simultaneously oxidised and reduced. One of the reacting substances in a disproportionation reaction always contains an element that can exist in atleast three oxidation states. 1×4

21O2 (aq) -→ 2H2O (1) +O2 (g)

i) Oxidation state of oxygen in peroxide is:

(a) 1

(b) 2

ii) Oxidation state of oxygen in water is:-

(a) 2

(b)-2

ii) Oxidation state of hydrogen in water is

(a) 2

(b) 2

iv) What is the oxidation state of Pb in PbO, ?

(a) 2 3. Which of the following

(a) BeH

4- Which of the following

(a) Ca

(b)

hydrides is electron precise hydride?

(b) NH

ions will cause hardness in water sample?

(b) Na

(d) 0

(d) CH4

(d) K

5- Photoelectric effect is maximum in (1) Cs

(b) Na

6- Plaster of Paris is hardened by

(a) Liberating CO

7- Which of the following

(a) AICI

(b) Hydration

is a Lewis acid? (b) MgCl2

8- The reason for small radius of Ga compared to Al is

(a) Poor screening effect of d and forbitals (c) Presence of higher orbitals

(d) Li

(d) Changing into CaCO

(d) BaCl2

(b) increase in nuclear charge (d) higher atomic number

9- How many moles of electrons weigh one kilogram? x

(a) 6.023 x 1023

(b) 9.108

101

6.023 X 104

(d) 9.108 X6.023 x 10%

10- A bivalent metal has an equivalent mass of 32. The molecular mass of the metal nitrate is:

(a) 168

(b) 192

(d) 182

11- The radius of the first Bohr orbit of hydrogen atom is 0.59 A. The radius of the third orbit of Het

(a) 8.46 A

(b) 0.705 A

(d) 2.65 A

will be

In the following questions (Q.no. 12 to 16) a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

a) Assertion and reason both are correct statements and reason is correct explanation b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.

for assertion.

c) Assertion is correct statement but reason is wrong statement. d) Assertion is wrong statement but reason is correct statement.

12- Assertion: It is impossible to determine the exact position and exact momentum of an electron simultaneously.

Reason: The path of an electron in an atom is clearly defined.

13- Assertion Noble gases have positive electron gain enthalpy: Reason: Noble gases have stable closed shell electronic configuration

14- Assertion: F is more electronegative than Cl. Reason: F has more electron affinity than Cl.

15- Assertion: Boiling point of cis-isomers are higher than trans- isomers. Reason: Dipole moments of cis-isomers are liigher than trans-isomers.

16- Assertion: BF molecule is planar but NFi is pyramidal. Reason: N atom is smaller than B.

SECTION – B

The following questions, Q. No 17 – 25 are short answer type and carry 2 marks each.

17- Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygen by mass.

(At. Mass Fe = 55.85, O 16)

18- If the diameter of the carbon atom is 0.15 nm, calculate the number of carbon atoms which can be placed side by side in a straight line across length of scale of length 20 cm long.

19- How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

20- Write the favourable factors for the formation of ionic bond.

21- Calculate the temperature of 4.0 mol of a gas occupying sdm at 3.32 bar.(R = 0.083 bar dmK mol-)

22- Discuss the principle and method of softening of hard water by ion-exchange resins.

Derive Ideal gas equation

23- Explain why is sodium less reactive than potassium.

24- Explain the difference in properties of diamond and graphite on the basis of their structures.

25- What are electrophiles and nucleophiles? Explain with examples.

SECTION –

No 26 -30 are Short Answer Type II carrying 3 mark each.

26- Yellow light emitted from a sodium lamp has a wavelength (A) of 580 nm. Calculate the frequency (v)

27- The enthalpy of combustion of methane, graphite and dihydrogen at 298K are -890.3 KJ mol, and the wavenumber (v) of the yellow light.

-393.5KJ mol and -285.8 KJ mol respectively. Calculate the enthalpy of formation of CH?

28- Enthalpies of formation of CO (g), CO2 (g), N20 (g) and N20 (g) are -110, -393, 81 and 9.7 KJ mol respectively. Find the value of AH for the reaction:

N204 (g) +3CO (g) – N20 (g) + 3CO2 (g)

29- Give the condensed and bond line structural formulas and identify the functional group(s) present, if any,

for:

(a) 2.2.4 Trimethylpentane

(b) 2 Hydroxy – 1. 2. 3 – propanetricarboxylic acid

30- Write down the products of ozonolysis of L. 2-dimethyl benzene (o – xylene). How does the result support Kekulé structure for benzene?

How is benzene prepared by decarboxylation? How does benzene react with fuming sulphuric acid?

SECTION D

Q.No 31 to 33 are long answer type carrying 5 marks each. 31 Complete the following reactions.

CH Br+ 2Na+BCH: dry ether

CH,-CH, + Cl

NIA

CH4 + H2O –

CH;-CH = CH2 + HBr

CaC +2H O

32- How are free radicals, carbocations and carbanions produced? Explain with examples and state their relative stabilities.

What is hyperconjugation effect? How does it differ from resonance effect? Briefly explain the significance of hyperconjugation effect.

33 (1) The equilibrium constant expression for a gas reaction is K =

[NH3 (02]5

(NO]*|H20]6

Write the balanced chemical equation corresponding to this expression

(ii) One mole of H20 and one mole of CO are taken in a 10 litre vessel and heated at 725 K. At equilibrium 40% of water (by mass) reacts with CO according to the equation:

HO (g) + CO (g) H2 (g) + CO2 (g)

Calculate the equilibrium constant for the reaction.