West Bengal Board Class 12 Chemistry Sample Papers 2011

Class 12
Sample Paper Of Chemistry

Time : 3.00 Hours]

[Maximum Marks : 100

Instructions

(1) This question paper contains 32 questions. All are compulsory.

(2) Write each new section with anew page and write answers of the questions in their order.

(3) Write your answers according to instructions pointwise and to the point. Draw figure and give reactions wherever required.'

(4) Use log-table provided by Board, or a simple calculator provided for your calculations.

(5) Use Pencil for figure drawing and Blue-pen for your writing in the Answer Book.

(6) Constants :

R = 1.987 Cal./ mole °K.

= 8.314 Joule/ mole °K.

1. Who proved the de-Broglie's principle experimentally? How?

2. Draw the structure of Diamond and write its type of hybridization.

3. Define : Colligative properties.
OR
Define : Osmosis.

4. What will be the change in entropy, when 18 grams of Water is converted into its vapour at 100°C temperature?
Heat of Vapourisation of Water is 9720 cal/mole.

5. Define : Cell Potential

6. Write uses of Sn02 (two).

7. Write any one chemical reaction to prepare Chlorine in laboratory.

8. State the type of classification of ligands exist in complex ion [Pt(en)2C12]2+

9. Calculate ratio of Neutron and Proton of the element obtained by emission of a- particle from 2 90Th

10. What are Isomorphous?

11. Write Van't-Hoff rule in terms of Stereo-isomers.

12. Draw electronic structure of Methanol.

13. Write : Decarboxylation reaction of Acetic acid.
OR
Write : Reaction to prepare Acetic anhydride from Acetic acid.

14. Diazotisation,reaction is carried out at a low temperature. Why?

15. How Dextran is produced? State its use.

16. What are Nucleoside and Nucleotide?

17. Explain the evolution of Spin Quantum Number.

18. Explain Raoult's law for the solution which possess solute gas in a liquid solvent.

19. Write short note on : Substitutional Solid Solution.

20. Write difference between Electro-chemical cell and`Electrolytic cell - (state 4 points).

21. Explain the equation of average rate of reaction by graph showing the change in concentration of reactants and products with time.

22. The first order reaction takes 20 minutes to complete 15% of its concentration, calculate what time will be required to complete its 75% concentration?
OR

The rate constant of a reaction is 2.Ox103min.-1 at 27 °C. If the temperature is increased by 20 °C, its value becomes three times. Calculate energy of activation.

23. On which principle the Langmuir adsorption isotherm depends? Write its hypothesis.

24. Uses' of adsorption (any four).

25. Give chemical reactions for preparation of K2Cr2O7.
OR
How photographic plate is. prepared? Explain the preparation.

26. Explain structure of complex ion in K2[Ni(CN)4] on the basis of hybridisation.

27.State magnetic moment of metal ion present in [Fe(H2O)6]3+ and [Fe(CN)6]3-. Give reason for their different values.

28. What is called Nuclides? State the element Z=90 atomic weight with 230 and 228 in the form of nuclides.

29. Write short note on Di-saccharides.

30. Give structural formula of a-amino acid obtained by hydrolysis of Protein. Write names of any two amino-acids occur in nature.294 Pu

31. Explain : Mordant Dyes.

OR

How Ceramics are obtained? Write names of ceramics used in cutting and grinding tools.

32. Write short note on :

Synthetic Sweetners.