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Public Exam Model Question Paper 2019 - 2020

11th Standard

Reg.No. :
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Chemistry

Time : 02:45:00 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. The number of molecules in 16g of methane is:

(a)

3.023 x 1023

(b)

6.023 x 1023

(c)

16/6.023 x 1023

(d)

6.023/3 x 1023

2. Splitting of spectral lines in an electric field is called

(a)

Zeeman effect

(b)

Shielding effect

(c)

Compton effect

(d)

Stark effect

3. d-block elements form _____ compounds.

(a)

ionic

(b)

covalent

(c)

metallic

(d)

both (a) and (b)

4. Water gas is

(a)

H2O(g)

(b)

CO + H2O

(c)

CO + H2

(d)

CO + N2

5. Consider the following statements
1. Alkali metals are soft.
2. Alkali metals show high reactivity
3. I.E of alkali metal decreases down the group
Which of the following statement(s) given above is/ are correct?

(a)

1 & 3

(b)

only I

(c)

2 & 3

(d)

1, 2 & 3

6. A gas such as carbon monoxide would be most likely to obey the ideal gas law at

(a)

High temperature and high pressure

(b)

High temperature and low pressure

(c)

Low temperature and high pressure

(d)

Low temperature and high pressure

7. In an adiabatic expansion of an ideal gas

(a)

w=-ΔU

(b)

w=ΔU+ΔH

(c)

ΔU=O

(d)

w = 0

8. The equilibrium constants of the following reactions are:

 N2 + 3H2 ⇌ 2NH3   : K1 N2 + O2 ⇌ 2NO      : K2 H2 + ½O2 ⇌ H2O   : K3

The equilibrium constant (K) for the reaction ;
${ 2NH }_{ 3 }+5/2{ O }_{ 2 }\overset { K }{ \rightleftharpoons } 2NO+{ 3H }_{ 2 }{ O },$ will be

(a)

$K_2^3{K_3\over K_1}$

(b)

$K_1{K_3^3\over K_2}$

(c)

$K_2{K_3^3\over K_1}$

(d)

$K_2{K_3\over K_1}$

9. At 100C the vapour pressure of a solution containing 6.5g a solute in 100g water is 732mm. If Kb = 0.52, the boiling point of this solution will be

(a)

102oC

(b)

100oC

(c)

101oC

(d)

100.52oC

10. Statement I : In sulphur hexafluoride, the central atom has more than eight valence electrons.
Statement II : The central atom can accommodate additional electron pairs by using outer vacant d orbitals.

(a)

Statements I and II are correct and statement II is the correct explanation of statement I

(b)

Statements I and II are correct but statement II is not the correct explanation of statement I.

(c)

Statement I is correct but statement II is wrong.

(d)

Statement I is wrong but statement II is correct.

11. The IUPAC name of the compound ${ CH }_{ 3 }-\underset { \overset { | }{ OH } }{ CH } -COOH$ is

(a)

2 – Hydroxypropionic acid

(b)

2 – Hydroxy Propanoic acid

(c)

Propan – 2– ol –1 – oic acid

(d)

1 – Carboxyethanol

12. Which one of the following is correct order of the stability of carbanions?

(a)

-C(CH3)3>-CH(CH3)2> -CH2-CH3 > -CH3

(b)

-CH3>-CH2-CH3> -CH(CH3)2> -(CH3)3

(c)

-CH(CH3)2>-H3 > -CH2-CH3 >-(CH3)3

(d)

-CH2-CH3>-CH(CH3)2>-CH3>-(CH3)3

13. Which among these is not associated with aliphatic compounds?

(a)

They contain (4n+2)$\pi$ electrons

(b)

They contain straight chain compounds

(c)

They contain branched chain compounds

(d)

They have appropriate number of H-atoms and functional groups.

14. In SN1, the rate of the reaction depends on the ______________.

(a)

nucleophile

(b)

medium

(c)

concentration of the substrate

(d)

none of the above

15. Identify the wrong statement in the following

(a)

The clean water would have a BOD value of more than 5 ppm

(b)

Greenhouse effect is also called as Global warming

(c)

Minute solid particles in air is known as particulate pollutants

(d)

Biosphere is the protective blanket of gases surrounding the earth

16. Part II

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

6 x 2 = 12
17. Calculate the equivalent mass of the following - Aluminium hydroxide

18. Consider the following electronic arrangements for the d5 configuration.
(a)

 $\upharpoonleft \downharpoonright$ $\upharpoonleft \downharpoonright$ $​​\upharpoonleft$

(b)

 $​​\upharpoonleft$ $​​\upharpoonleft$ $​​\upharpoonleft$ $\upharpoonleft \downharpoonright$

(c)

 $​​\upharpoonleft$ $​​\upharpoonleft$ $​​\upharpoonleft$ $​​\upharpoonleft$ $​​\upharpoonleft$

(i) which of these represents the ground state
(ii) which configuration has the maximum exchange energy.

19. Write balanced chemical equation for the following processes
(a) heating calcium in oxygen
(b) heating calcium carbonate
(c) evaporating a solution of calcium hydrogen carbonate
(d) heating calcium oxide with carbon

20. Under what conditions, do real gases behave ideally?

21. Define Heat. Give its unit

22. If there is no change in concentration, why is the equilibrium state considered dynamic?

23. Represent the bond formation in [Fe(CN)6]4- and BF3-NH3

24. The ammonia evolved form 0.20 g of an organic compound by kjeldahl method neutralised 15ml of N/20 sulphare acid solution. Calculate the percentage of Nitrogen.

25. Reagents and the conditions used in the reactions are given below. Complete the table by writing down the product and the name of the reaction.

Reaction     Product     Name of
the reaction
${ CH }_{ 3 }{ CH }_{ 2 }OH+{ SOCl }_{ 2 }\overset { pyridine }{ \longrightarrow } ?$    ------ --------
${ CH }_{ 3 }{ CH }_{ 2 }Br+AgF\longrightarrow ?$ ------- --------
${ C }_{ 6 }{ H }_{ 5 }Cl+Na\overset { ether }{ \longrightarrow } ?$ ------- ---------
26. Part III

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

6 x 3 = 18
27. A piece of cut apple becomes brown. Why? Can you prevent it by a simple method

28. Describe the Autbau principle

29. Mention any two anomalous properties of second period elements.

30. Complete the following reactions.
Al4C3 + D2O ➝?
CaC2 + D2O ➝?
Mg3N2 + D2O ➝?
Ca3P2 + D2O ➝?

31. Why sodium hydroxide is much more water soluble than chloride?

32. A mixture of gases contains 4.76 mole of Ne, 0.74 mole of Ar and 2.5 mole of Xe. Calculate the partial pressure of gases, if the total pressure is 2 atm. at a fixed temperature. Solve this problem using Dalton's law.

33. In a constant volume calorimeter:3.5g of a gas with molecular weight 28 was burnt in excess oxygen at 298 K. The temperature of the calorimeter was found to increase from 298 K to 298.45 K due to the combustion process. Given that the calorimeter constant is 2.5 kJ K-1. Calculate the enthalpy of combustion of the gas in kJ mol-1

34. The observed depression in freezing point of water for a particular solution is 0.093o C. Calculate the concentration of the solution in molality. Given that molal depression constant for water is 1.86 KKg mol-1.

35. While writing the resonance structures, what are the rules to be followed?

36. Part IV

5 x 5 = 25
37. An organic compound was found to contain carbon = 40.65%, hydrogen = 8.55% and Nitrogen = 23.7%. Its vapour density was found to be 29.5. What is the molecular formula of the compound?

38. List out the important features of quantum mechanical model of atom

39. Calculate the effective nuclear charge experienced by the 4s electron in potassium atom.

40. An isotope of hydrogen (A) reacts with diatomic molecule of element which occupies group number 16 and period number 2 to give compound (B) is used as a moderator in nuclear reaction. (A) adds on to a compound ( C), which has the molecular formula C3H6 to give (D). Identify A, B, C and D.

41. An element A belonging to group 2 and period 2 reacts with chlorine at an elevated temperature to give compound (B) compound B combines with LiAIH4 to form compound (C). Which is an hydride identify A, B, and C?

42. List the characteristics of entropy:

43. Discuss the salient features of VBT.

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. An organic compound Ⓐ of molecular formula CH2O reacts with methyl magnesium iodide followed by acid hydrolysis to give Ⓑ of molecular formula C2H60. Ⓑ on reaction with PCIs gives ©. ©on reaction with alcoholic KOH gives Ⓓan alkene as the product. Identify Ⓐ, Ⓑ ©, Ⓓ and explain the reactions involved.

46. How is acid rain formed? Explain its effect