p - Block Elements - II Model Question Paper

12th Standard EM

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. On hydrolysis, PCl3 gives

(a)

H3PO3

(b)

PH3

(c)

H3PO4

(d)

POCl3

2. P4O6 reacts with cold water to give

(a)

H3PO3

(b)

H4P2O7

(c)

HPO3

(d)

H3PO4

3. Among the following, which is the strongest oxidizing agent?

(a)

Cl2

(b)

F2

(c)

Br2

(d)

l2

4. Which is dibasic?

(a)

Orthophosphoric acid

(b)

Pyrophosphoric acid

(c)

Orthophosphorus acid

(d)

Hypophosphorus acid

5. S-S bond is present in

(a)

H2S2O7.

(b)

H2SO5

(c)

H2S2O6

(d)

H2S2O6

6. 5 x 2 = 10
7. Chalcogens belongs to p-block. Give reason.

8. Give the uses of helium.

9. What is the hybridisation of iodine in IF7? Give its structure?

10. Elements of group 16 show lower value of first ionization enthalpy compared to group 15, why?

11. Although $\triangle$H of fluorine is less negative than that of chlorine, but fluorine is a stronger oxidising agent than chlorine, why?

12. 5 x 3 = 15
13. Give the uses of sulphuric acid.

14. Write the reason for the anamolous behaviour of Nitrogen.

15. Write the valence shell electronic configuration of group-15 elements.

16. Explain the commercial method of preparation of nitric acid. (or) How nitric acid is prepared by Ostwald's process

17. Name a reaction for the estimation of Ozone.

18. 4 x 5 = 20
19. What happens when PCl5 is heated?

20. Suggest a reason why HF is a weak acid, whereas binary acids of the all other halogens are strong acids.

21. What type of hybridisation occur in
a) BrF5
b) BrF3

22. An amorphous solid (A) burns in air to form a gas (B)which turns lime water milky. The gas is also produced as a byproduct during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO4 solution and reduces Fe3+ to Fe2+. Identify the solid 'A' and the gas 'B' and write the reactions involved.