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#### Sample 3 Mark Creative Questions (New Syllabus) 2020

12th Standard EM

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 99

Part A

33 x 3 = 99
1. Explain alkali leaching in the extraction of aluminum,

2. Write the molecular composition of the following ores and mentions it metal : magnetite) calamine and bauxite.

3. Mention the uses of copper

4. How is boron trifluoride obtained from boron trioxide?

5. Give 3 uses of carbon monoxide.

6. Explain the structure of ammonia

7. Complete the following reactions
(l) Cl2+ H20$\longrightarrow$?
(ii) XeF6 + 2H20 $\longrightarrow$ ?
(Iii) XeF6 + 2H20$\longrightarrow$?

8. What are the general properties of f-block elements? (Lanthanides and Actinides)
(i) Electronic configuration
(ii) Oxidation state
(iii) Radii of tripositive ions.

9. Give reason for the following:
(i) A transition metal exhibits highest oxidation state in oxides and fluorides.
(ii) Cu2+ is unstable in an aqueous solution.

10. Explain the preparation of potassium permanganate from pyrolusite.

11. Which is the last element in the series of the actinoids? Write the electronic configuration of this element comment on the possible oxidation state of this element.

12. Name some metal complexes, that are present in our biological system and their role in it.

13. Silver crystallines in fcc lattice. If edge length of the cell is 4.07 x 10-8 em and density is 10.5 g cm-3. Calculate the atomic mass of silver

14. How do the spacings of the three planes (100), (101) and (111) of simple cubic lattice vary?

15. Distinguish the following.
Crystal lattice and unit cell.

16. The energy of achivation for the formation of hydrogen iodide is 150 kJ mol-1 The rate constant of this reaction at 673 K is 2.3 X 10-3. Calculate the rate constant at 773 K.

17. The rate constant for a first order reaction is 60 S-1. How much time will it take to reduce the initial concentration of the reactant to its ${ \frac { 1 }{ 16 } }^{ th }$ value?

18. For an aqueous solution of NH4CI, prove that [H+ ] = $\sqrt { { K }_{ n }.C }$

19. 0.1 M solution of two electrolytes P and Q have specific conductance 4 x 10-4 S cm-1 and 6 x 10-6 S cm-1 respectively. Which among the following will have greater resistance to the flow of current? Give reason.

20. Write the reactions taking place in anode and cathode of a mercury button cell. Give the over all redox reaction of the cell with the emf generation

21. Show that SHE can act both as a anode as well as cathode.

22. How is coagulation brought about by addition of electrolytes?

23. Write a note on Friedel Crafts reaction of anisole.

24. Account for the following: (i) Phenol has a smaller dipole moment than methanol, (ii) Phenols do not give protonation reaction readily.

25. Ethers should not be heated to dryness. Why? (OR) How does diethyl ether react WIith oxygen.?

26. Explain Stephen's reaction.

27. What is Malachite green dye? Explain its preparation?

28. Write a note on the basicity of amines

29. Write a note on structure of amine.

30. Write the product formed when HCN reacts with glucose.

31. What are carbohydrates? Give two examples.

32. Write a short note on Antioxidants.

33. Give examples for (i) addition polymer, (ii) Synthetic rubbers, (iii) Condensation polymers, (iv) formaldehyde resins.