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#### Public Exam Model Question Paper June 2020

11th Standard

Reg.No. :
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Chemistry

Time : 02:30:00 Hrs
Total Marks : 70

Part I

Choose the most suitable answer from the given four alternatives and write the option code with the corresponding answer.

15 x 1 = 15
1. Identify the incorrect statement about a compound.

(a)

A molecule cannot be separated into its constituent elements by physical methods of separation

(b)

A molecule of a compound has atoms of different elements

(c)

A compound retains the physical properties of its constituent element

(d)

The ratio of atoms of different elements in a compound is fixed

2. The ratio of de Broglie wavelengths of a deuterium atom to that of an u - particle, when the velocity of the former is five times greater than that of later, is

(a)

4

(b)

0.2

(c)

2.5

(d)

0.4

3. Which of the following N3-, O2-, F- is largest in size?

(a)

N3-

(b)

O2-

(c)

F-

(d)

All of these

4. Non-stoichiometric hydrides are formed by

(a)

(b)

carbon, nickel

(c)

manganese, lithium

(d)

nitrogen, chlorine

5. Half life of francium is _______

(a)

12.3 years

(b)

12.3 mins

(c)

21 years

(d)

21 mins

6. The SI unit of pressure is __________.

(a)

Nm-2 Kg-1

(b)

Pascal

(c)

bar

(d)

atmosphere

7. An ideal gas expands from the volume of 1 x 10-3 m3 to 1 x 10-2 m3 at 300 K against a constant pressure at 1 x 105 Nm-2. The work done is

(a)

- 900 J

(b)

900 kJ

(c)

270 kJ

(d)

-900 kJ

8. The equilibrium constant for a reaction at room temperature is K1 and that at 700 K is K2. If K1 > K2, then

(a)

The forward reaction is exothermic

(b)

The forward reaction is endothermic

(c)

The reaction does not attain equilibrium

(d)

The reverse reaction is exothermic

9. Phenol dimerises in benzene having van't Hoff factor 0.54. What is the degree of association?

(a)

0.46

(b)

92

(c)

46

(d)

0.92

10. During the formation of a chemical bond ________.

(a)

energy decreases

(b)

energy increases

(c)

energy remains zero

(d)

energy remains constant

11. The IUPAC name of the compound ${ H }_{ 3 }C-\overset { \underset { | }{ { CH }_{ 3 } } }{ \underset { \overset { | }{ { CH }_{ 3 } } }{ C } } -CH=C{ \left( { CH }_{ 3 } \right) }_{ 2 }$ is

(a)

2,4,4 – Trimethylpent -2-ene

(b)

2,4,4 – Trimethylpent -3-ene

(c)

2,2,4 – Trimethylpent -3-ene

(d)

2,2,4 – Trimethylpent -2-ene

12. Which one of the following has least acidic character?

(a)

HCOOH

(b)

CH3COOH

(c)

CH2CICOOH

(d)

CCl3COOH

13. The most stable conformation of Butane is

(a)

Gauche-form

(b)

Partially eclipsed form

(c)

Anti-form

(d)

Eclipsed form

14. Which one of the following is used as an insecticide and as a soil sterilising agent?

(a)

Chloroform

(b)

Chloral

(c)

Chloropicrin

(d)

Tetrachloromethane

15. Assertion (A): Excessive use of chlorinated pesticide causes soil and water pollution.
Reason (R) : Such pesticides are non-biodegradable.

(a)

Both (A) and R are correct and (R) is the correct explanation of (A)

(b)

Both (A) and R are correct and (R) is not the correct explanation of (A)

(c)

Both (A) and R are not correct

(d)

(A) is correct but( R) is not correct

16. Part II

Answer any 6 questions. Question no. 24 is compulsory.

6 x 2 = 12
17. Define - Empirical formula of a compound

18. For each of the following, give the sub level designation, the allowable m values and the number of orbitals
(i) n = 4, 1=2, (ii) n = 5, 1=3 (iii) n = 7, 1=0

19. Substantiate lithium fluoride has the lowest solubility among group one metal fluorides.

20. Explain what happens of a balloon is moved from an ice-cold water bath to a boiling water bath.

21. What are spontaneous reaction? Give three examples for spontaneous reaction.

22. Deduce the Vant Hoff equation.

23. Calculate the formal charge on the carbon atom and oxygen atom in the structure:$\overset { .. }{ \underset { .. }{ O } } =C=\overset { .. }{ \underset { .. }{ O } }$

24. Describe the reactions involved in the detection of nitrogen in an organic compound by Lassaigne method.

25. Give reasons for polarity of C-X bond in halo alkane.

26. Part III

Answer any 6 questions. Question no. 33 is compulsory.

6 x 3 = 18
27. Identify the type of redox reaction taking place in the following
$\overset { 0 }{ { Ca }_{ (s) } } +\overset { +1 }{ 2 } \overset { -2 }{ { H }_{ 2 }O_{ (l) } } \longrightarrow \overset { +2 }{ Ca } \overset { -2+1 }{ { (0H) }_{ 2(aq) } } +\overset { 0 }{ H } _{ 2(g) }$

28. State and explain pauli's exclusion principle

29. Energy of an electron in the ground state of the hydrogen atom is -2.8 x 10-18 J. Calculate the ionisation enthalpy of atomic hydrogen in terms of kJ mol-1.

30. Give a brief account of metallic (interstitial) hydrides.

31. Write balanced chemical equation for each of the following chemical reactions.
(i) Lithium metal with nitrogen gas
(ii) heating solid sodium bicarbonate
(iii) Rubidum with oxgen gas
(iv) solid potassium hydroxide with CO2
(v) heating calcium carbonate
(vi) heating calcium with oxygen

32. What is meant by Boyle temperature (or) Boyle point? How is it related with compression point?

33. What are state and path functions? Give two examples

34. 2.82 g of glucose is dissolved in 30 g of water. Calculate the mole fraction of glucose and water.

35. What are the possible types of electron movement? Represent them by clearly indicating the electron shift.

36. Part IV

5 x 5 = 25
37. Balance the following equation by ion electron method.
Zn + NO3- ⟶ Zn + NH4+2

38. A neutral atom of an element has 2K, 8L and 5M electrons. Find out the following.
(i) Atomic number of the element  (ii) Total number of s-electrons  (iii) Total number of p-electrons (iv) Number of protons in the nucleus  (v) Valency of the element

39. Give the characteristics of p-block elements.

40. Explain preparation of hydrogen using electrolysis.

41. Distinguish between alkali metals and alkaline earth metals.

42. What are thermochemical equation? What are the conventions adopted in writing thermochemical equation?

44. Give IUPAC names for the following compounds
1) CH3 – CH = CH – CH = CH – C ≡ C – CH3
2)
3) (CH3)3 C – C ≡ C – CH (CH3)2
4) ethyl isopropyl acetylene
5) CH ≡ C – C ≡ C – C ≡ CH

45. Explain the mechanism involved in bimolecular nucleophilic substitution reaction.

46. What are particulate pollutants? Explain any three.