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Model 3 Mark Book Back Questions (New Syllabus) 2020

12th Standard EM

    Reg.No. :


Time : 01:00:00 Hrs
Total Marks : 57

    Part A

    19 x 3 = 57
  1. Explain the electrometallurgy of aluminium

  2. Describe the structure of diborane

  3. Give a reason to support that sulphuric acid is a dehydrating agent.

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

  5. Give one test to differentiate [Co(NH3)5Cl]SO4 and [Co(NH3)5SO4]Cl.

  6. Explain Schottky defect.

  7. The rate of formation of a dimer in a second order reaction is 7.5 X 10-3mol L-1 s-1 monomer concentration. Calculate the rate constant.

  8. A gas phase reaction has energy of activation 200 kJ mol-1. If the frequency factor of the reaction is is 1.6 X1013s-1 Calculate the rate constant at 600 K.(e-40.09=3.8X10-48)

  9. Explain common ion effect with an example

  10. Derive an expression for the hydrolysis constant and degree of hydrolysis of salt of strong acid and weak base

  11. 0.1M NaCl solution is placed in two different cells having cell constant 0.5 and 0.25cm-1 respectively. Which of the two will have greater value of specific conductance.

  12. What happens when a colloidal sol of Fe(OH)3 and AS2O3 are mixed?

  13. Write the mechanism of acid catalysed dehydration of ethanol to give ethane.

  14. Compound (A) C6H12O2 on reduction with LiAlH4 yields two compounds B and C. The compound (B) on oxidation gave (D) which on treatment with aqueous alkali and subsequent heating furnished E. The latter on catalytic hydrogenation gave (C). Compound (D) on oxidation gave monobasic acid (molecular formula weight = 60). Deduce the structure of (A), (B), (C), (D) and (E).

  15. How will you convert benzaldehyde into the following compounds?
    (i) benzophenone
    (ii) benzoic acid
    (iii) hydroxyphenylaceticacid.

  16. Account for the following
    i. Aniline does not undergo Friedel – Crafts reaction
    ii. Diazonium salts of aromatic amines are more stable than those of aliphatic amines
    iii. pKb of aniline is more than that of methylamine
    iv. Gabriel phthalimide synthesis is preferred for synthesising primary amines.
    v. Ethylamine is soluble in water whereas aniline is not
    vi. Amines are more basic than amides
    vii. Although amino group is o – and p – directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m – nitroaniline.

  17. How will you prepare propan – 1- amine from
    i) butane nitrile
    ii) propanamide
    ii) 1- nitropropane

  18. Why carbohydrates are generally optically active.

  19. Explain the mechanism of cleansing action of soaps and detergents


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