a) Illustrate the following name reactions giving a chemical equation in each case:
i) Clemmensen reaction ii) Cannizzaro's reaction
b) An organic compound contains 69.70% carbon, 11.63% hydrogen and the rest oxygen; molecular mass 86. It does not reduce Tollens' reagent, but forms an addition compound with sodium hydrogen sulphite and gives a positive iodoform test. On vigorous oxidation it gives ethanoic and propanoic acids. Derive the possible structure of the compound A.
i) Clemmensen reaction ii) Cannizzaro's reaction
b) An organic compound contains 69.70% carbon, 11.63% hydrogen and the rest oxygen; molecular mass 86. It does not reduce Tollens' reagent, but forms an addition compound with sodium hydrogen sulphite and gives a positive iodoform test. On vigorous oxidation it gives ethanoic and propanoic acids. Derive the possible structure of the compound A.
Answer: (a)(i) C₆H₅COCH₃ →Zn(Hg)/HCl→ C₆H₅C₂H₅; (ii) 2C₆H₅CHO + NaOH → C₆H₅CH₂OH + C₆H₅COONa. (b) A = pentan-2-one.
Solution
(a)(i)
(ii)
(b) C:H:O = 5.81:11.63:1.16 → CHO (M = 86 ✓). Ketone (no Tollens), methyl ketone (iodoform ✓), bisulphite adduct ✓; oxidation splitting into C + C acids fixes
(ii)
(b) C:H:O = 5.81:11.63:1.16 → CHO (M = 86 ✓). Ketone (no Tollens), methyl ketone (iodoform ✓), bisulphite adduct ✓; oxidation splitting into C + C acids fixes
CBSE Class 12 Board · 2009 · Delhi · Subjective