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#### Model 5 Mark Creative Questions (New Syllabus) 2020

12th Standard EM

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 175

Part A

35 x 5 = 175
1. Explain refining of nickel by mond's process

2. What is zone refining? Describe the principle involved in the purification of the metal by this method.

3. Distinguish between diamond and graphite.

4. Give a detailed account on allotropes of sulphur.

5. Complete the following equations:
a. 4NaCI + MnO2 + 4H2SO4 $\longrightarrow$?
b. 6XeF4 + 12H2O$\longrightarrow$  ?

6. Explain the Deacon's process

7. An element A occupies group number 15 and period number 3, reacts with chlorine to give compound B. The compound B on hydrolysis gives a dibasic acid C. The compound C on heating undergoes auto oxidation and reduction to give a tribasic acid D. Identify the elements A, compounds B, C and D. Write the reactions

8. Write a short note on the oxidation states of 3d series elements.

9. Give the postulates and limitation of Werner's theory of co-ordination compounds.

10. What are the salient feature of crystal field theory?

11. Ionic solids, which have anionic vacancies due to metal excess defect, develop colour. Explain with the help of a suitable example.

12. How are crystals classified?

13. The conversion of molecules x to y follows second order kinetics. Its concentration of x is increased to three times how will it affect the rate of formation of y?
For the reaction x ➝ y as it follows second order kinetics wherefore the rate of formation of y?

14. A first order reaction completes 25% of the reaction in 100 mins. What are the rate constant and half life values of the reaction?

15. Calculate the pH of 0.1 M acetic acid if its ionisation constant Ka = 1.8 X 10-5.

16. Calculate the pH of 0.001 MHCI solution.

17. Calculate the pH of 0.1 M NH4OH if Kb = 1.75 x 10-5

18. To 1M solution of AgNO3, 0.75 F quantity of current is passed. What is the concentration of the electrolyte, AgNO3 remaining in the solution?

19. If E1 = 0.5 V corresponds to Cr3++ 3e- ➝ Cr(s) and E= 0.41V corresponds to Cr3++ e- ➝ Cr2+ reactions, calculate the emf (E3) of the reaction Cr2++ 2 e- ➝ Cr(s)

20. Write the electrochemical mechanism of corrosion.

21. Give the special characteristics of enzyme catalysed reactions.

22. Name the method to deduce the charge of the sol particle. Explain it with a neat diagram.

23. An organic compound A of molecular f formula C6H6O gives violet colouration with neutral FeCI3• Compound A on treatment with metallic Na gives compound B. Compound B on treatment with CO2 at 400 K under pressure gives C. This product on acidification gives compound D (C7H6O3) which is used in medicine. Identify A) B) C and D and explain the reactions.

24. An organic compound A (C2H6O2) liberates hydrogen with metallic sodium. Compound A when heated with anhydrous zinc chloride ultimately gives B (C2H4O) whereas) when heated with cone. phosphoric acid gives C (C4H10O3). A on oxidation with acidified K2Cr2O7gives compound D (CH2O2). Identify A) B)C and D. Explain the reactions involved.

25. What are ethers? Write note on simple and mixed ethers with examples.

26. An organic compound 'A is a sodium salt of phenolic acid with molecular formula C7H5O3Na. 'A on heating with soda lime gives compound 'B' of molecular formula C6H6O. 'B' gives violet colour with neutral ferric chloride. 'B' on treatment with C6H5COCI in the presence of NaOH gives an ester 'C' Identify 'A', 'B' and 'C'. Explain the reactions.

27. Discuss the mechanism of aldol condensation.

28. Account for reducing nature of formic acid.

29. An organic compound (A) of molecular formula C7H6O is not reduced by Fehling's solution but will undergo Cannizzaro reaction. Compound (A) reacts with aniline to give compound (B). Compound (A) also reacts with Cl2 in the presence of catalyst to give compound (C). Identify (A (B) and (C) and explain the reactions.

30. An organic compound (A) C2H3OCI on treatment with Pd and BaSO4 gives (B) C2H4O which answers iodoform test. (B) when treated with cone. H2SO4 undergoes polymerisation to give (C) .a cyclic compound. Identify (A), (B) and (C) and explain the reactions.

31. Ail organic compound. (A) C7H6O reduces Tollens reagent.. Compound (A) reacts with acetic anhydride in the presence of anhydrous sodium acetate and gives an unsaturated acid (B). Compound (A) reacts with acetone in the presence of alkali and gives (C). What are (A)(B) and (C) Explain the reactions.

32. Accuount for
i) Reduction of CH3CH gives CH3CH2NHwhile CH3NC gives (CH3)2NH.
ii) (CH3)2NH requires two molar proportion of CH3I to give the same crystalline product formed by (CH3)2N with one mole of CH3l.
iii) Nitration of aniline with conc.HNO3 may end up with same meta nitro product.
iv) p-toluidine is a stronger base than p-nitroaniline.

33. Give the uses of carbohydrates.

34. Explain the classification of hormones.

35. Explain the classification of polymers based on their structure and mode of synthesis.