#### 11th Public Exam March 2019 Model Question

11th Standard

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Chemistry

Time : 02:30:00 Hrs
Total Marks : 70
15 x 1 = 15
1. 22 g of CO2 contains ____________ molecules of CO2.

(a)

6.023 x 10-23

(b)

6.023 x 1023

(c)

3.0115 x 1023

(d)

3.0115 x 10-23

2. For d-electron, the orbital angular momentum is

(a)

$\frac { \sqrt { 2 } h }{ 2\pi }$

(b)

$\\ \frac { \sqrt { 2h } }{ 2\pi }$

(c)

$\frac { \sqrt { 2\times 4 } h }{ 2\pi }$

(d)

$\frac { \sqrt { 2\times 4 } h }{ 2\pi }$

3. Ionic radii vary in:
(1) inverse proportion to the effective nuclear charge
(2) inverse proportion to the square of the effective nuclear charge.
(3) direct proportion to the screening effect.
(4) direct proportion to the square of screening effect

(a)

1,2

(b)

1,3

(c)

2,3

(d)

2,4

4. Tritium nucleus contains

(a)

1 p+0 n

(b)

2 p+1 n

(c)

1 p + 2 n

(d)

none of these

5. sodium is stored in

(a)

alcohol

(b)

water

(c)

kerosene

(d)

none of these

6. Gases deviate from ideal behavior at high pressure. Which of the following statement(s) is correct for non-ideality?

(a)

at high pressure the collision between the gas molecule become enormous

(b)

at high pressure the gas molecules move only in one direction

(c)

at high pressure, the volume of gas become insignificant

(d)

at high pressure the intermolecular interactions become significant

7. The correct thermodynamic conditions for the spontaneous reaction at all temperature is

(a)

ΔH<0 and ΔS>0

(b)

ΔH<0 and ΔS<0

(c)

ΔH>0 and ΔS=0

(d)

ΔH>0 and ΔS>0

8. For the reaction $A+3B\rightleftharpoons 2C+D$ initial mole of A is twice that of B.1f at equilibrium moles of B and C are equal, then percent of B reacted is

(a)

10%

(b)

20%

(c)

40%

(d)

60%

9. Which of the following concentration terms is/are independent of temperature

(a)

molality

(b)

molarity

(c)

mole fraction

(d)

9a) and (c)

10. H2O is polar, whereas BeF2 is not It is because

(a)

The electronegativity of F is greater than that of O.

(b)

H2O involves hydrogen bonding whereas BeF2 is a discrete molecule

(c)

H2O is linear and BeF2 is angular

(d)

H2O is angular and BeF2 is linear

11. In an organic compound, phosphorus is estimated as

(a)

Mg2P2O7

(b)

Mg3(PO4)2

(c)

H3PO4

(d)

P2O5

12. Which of the group has highest +I effect?

(a)

CH3-

(b)

CH- CH-

(c)

(CH3)2 - CH-

(d)

(CH3)3 - C-

13. In the commercial gasonlines, the type of hydrocarbons which are more desirable is

(a)

Linear unsaturated hydrocarbon

(b)

Toluene

(c)

Branched hydrocarbon

(d)

Straight-chain hydrocarbon

14. ________________is used in the treatment of goitre

(a)

Halothane

(b)

Benzoquinone

(c)

Chloromycetin

(d)

Thyroxine

15. Assertion (A): Oxygen plays a key role in the troposphere
Reason (R): Troposphere is not responsible for all biological activities

(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. 6 x 2 = 12
17. 3 grams of hydrogen reacts with 29g of O, to yield H2O. Calculate the amount of one of the reactants which remains unreacted.

18. How many radial nodes for 2s, 4p, 5d and 4f orbitals exhibit? How many angular nodes

19. Would you expect the first ionization enthalpies of two isotopes of the same element to be the same or different? Justify your answer.

20. Identify the elements that are in gaseous state under normal atmospheric conditions.

21. For a gaseous homogeneous reaction at equilibrium, number of moles of products are greater than the number of moles of reactants. Is KC is larger or smaller than KP.

22. Does H2O and H2S possess same bond, angle? Explain

23. Write the molecular formula of the first six members of homologous series of nitro alkanes.

24. Write short notes on (i) +E effect and (ii) -E effect

25. Mention any three methods of preparation of haloalkanes from alcohols.

26. 6 x 3 = 18
27. What is the difference between molecular mass and molar mass? Calculate the molecular mass and molar mass for carbon monoxide.

28. What are the reasons behind the Moseley's attempt in finding atomic number?

29. Do you think that heavy water can be used for drinking purposes?

30. When the driver of an automobile applies brake, the passengers are pushed toward the front of the car but a helium balloon is pushed toward back of the car. Upon forward acceleration the passengers are pushed toward the front of the car. Why?

31. Show that $\Delta$U = nCv (T2 - T1) and $\Delta$H = nCp(T2 - T1).

32. An aqueous solution of 2% nonvolatile solute exerts a pressure of 1.004 bar at the boiling point of the solvent. What is the molar mass of the solute when PA is 1.013 bar?

33. What is the difference between distillation, distillation under reduced pressure and steam distillation?

34. Explain the molecular orbirtal structure of benzene.

35. Even though the use of pesticides increases the crop production, they adversely affect the living organisms. Explain the function and the adverse effects of the pesticides.

36. 5 x 5 = 25
37. Balance the following equation by oxidation number method:
P + HNO3 $\rightarrow$H3PO4 + NO2 + H2O

38. Why the first ionisation enthalpy of sodium is lower than that of magnesium while its second ionisation enthalpy is higher than that of magnesium.

39. An element (A) belonging to group number 1 and period number 3 react with dihydrogen to form anhydride (B). The element (A) reacts with the universal solvent to give a strong base (C). Identify A, B, and C.

40. Describe briefly the biological Importance of Calcium and magnesium

41. Find the pressure of 5 mole CI2 gas filled in a 2 litre vessel at 27 °C temperature.

42. List the characteristics of Gibbs free energy

43. The equilibrium constant at 298 K for a reaction is 100.
A + B $\rightleftharpoons$ C + D
If the initial concentration of all the four species is 1 M, the equilibrium concentration of D (in mol lit-1) will be

44. Describe tautomerism with relevant examples.

45. Give a detailed account on the different mechanisms followed in elimination reaction.

46. How does classical smog differ from photochemical smog?