Qp chem 12

Qp chem

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 5 are very short-answer questions and carry

1 mark each.

(iii) Questions number 6 to 10 are short-answer questions and carry 2 marks

each.

(iv) Questions number 11 to 22 are also short-answer questions and carry

3 marks each.

(v) Questions number 24 to 26 are long-answer questions and carry 5 marks

each.

(vi) 23 is a value based question

(vii) Use Log Tables, if necessary. Use of calculators is not allowed.

1. What is a ‘shape selective catalyst’ ?

2. What is the role of CO2 in the extractive metallurgy of aluminium from its ore?

The aluminate in solution is neutralized by CO2 gas and hydrated Al2O3 is precipitated

3. Draw the structure of XeOF4

4.

5. Done

2 marks

6. Calculate emf of the following cell at 25°C:

Fe | Fe2+ (0.001 M) || H+ (0.01 M) | H2 (g) (1 bar) | Pt(s)

E° (Fe2+ | Fe) = –0.44 V E° (H+ | H2) = 0.00 V

7.

8. Calculate the mass of compound (molar mass = 256 g mol ) to be dissolved in 75 g of benzene

to lower its freezing point by 0.48 K (Kf = 5.12 K kg mol ).

9.

10. Give a chemical test to distinguish between each of the following pairs of compounds :

(i) Aniline and Benzylamine

(ii) Ethylamine and Aniline

OR

How are the following conversions carried out ?

(i) Propene to Propan-2-ol

(ii) Ethyl chloride to Ethanal

Or

3 marks

11.

Iv part: Write a distinguishing feature of a metallic solid compared to an ionic solid.

Conductance in metallic solid is through electrons whereas in ionic solid is through ions in

molten state or aqueous state. (or any other)

12.

13.

14. Give reasons for the following :

a) Transition metals exhibit a wide range of oxidation states.

b) Cobalt(II) is very stable in aqueous solutions but gets easily oxidised in the presence of

strong ligands.

c) Actinoids exhibit a greater range of oxidation states than lanthanoids.

Or

15. A)Which of the following is a disaccharide: starch, maltose, fructose, glucose?

b)Differentiate b/w fibrous and globular protein.

c)Write name of vitamin whose deficiency causes bone deformities in children.

Ans-page 340 q21

16.

17. done

18. done

19.

20. Ans- pg39/40 arihant

21. (ans on page 368-369 arihant)

22. Ans pg 175 arihant

23. done

5 marks

24.

25.

26.