#### 12th Standard English Medium Chemistry Reduced Syllabus Three mark Important Questions with Answer key - 2021(Public Exam )

12th Standard

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Chemistry

Time : 02:00:00 Hrs
Total Marks : 75

Part A

25 x 3 = 75
1. Explain zone refining process with an example using the Ellingham diagram given below.

2. Explain alkali leaching in the extraction of aluminum.

3. What is auto-reduction?

4. Describe the structure of diborane.

5. How is aluminum chloride prepared from aluminum?

6. How is CO2 manufactured?

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

8. Explain the commercial method of preparation of nitric acid.

9. Which is more stable? Fe3+ or Fe2+ - explain.

10. Write chemical equations for the reactions involved in the manufacture of potassium permanganate from pyrolusite ore.

11. What are the uses of potassium dichromate?

12. What is linkage isomerism? Explain with an example

13. Draw the structures of geometrical isomers of [Fe(NH3)2 (CN)4]-

14. Explain Bonding is metal carbonyls.

15. Write short note on metal excess and metal deficiency defect with an example.

16. Classify the following solids in different categories based on the nature of intermolecular force operating in them: Potassium sulphate, tin, benzene, urea, ammonia, water, zinc sulphide, graphite, rubidium, argon, silicon carbide.

17. Explain briefly the collision theory of bimolecular reactions.

18. Prove that the time required for the completion ${ \frac { 3 }{ 4 } }^{ th }$ of the reaction of a first order is twice the time required for the completion of a half of the reaction.

19. Derive an expression for Ostwald’s dilution law.

20. Calculate the pH of 0.1M CH3COOH solution. Dissociation constant of acetic acid is $1.8\times10^{-5}$.

21. Can Fe3+ oxidises Bromide to bromine under standard conditions?
Given: ${ E }_{ { Fe }^{ 3+ }|{ Fe }^{ 2+ } }^{ 0 }=0.771$
$\\ { E }^{0}_{ { Br }_{ 2 }|{ Br }^{ - } }=1.09V$.

22. Addition of Alum purifies water. Why?

23. Write the structure of the aldehyde, carboxylic acid and ester that yield 4- methylpent -2-en-1-ol.

24. How will you convert benzaldehyde into the following compounds?
(i) benzophenone

25. Why carbohydrates are generally optically active.