Question

An organic compound ‘A’ with molecular formula $C_2{H}_4{O}_2$ is widely used as a preservative in pickles. It reacts with ethanol to form a sweet-smelling compound ‘B’. Identify A and B.

• A. A – ${\mathrm{CH}}_3{\mathrm{COCH}}_3$;
  B – ${\mathrm{CH}}_3{\mathrm{COOCH}}_3$
• B. A – ${\mathrm{CH}}_3{\mathrm{COCH}}_3$;
  B – ${\mathrm{CH}}_3{\mathrm{COOC}}_2{H}_5$
• C. A – ${\mathrm{CH}}_3\mathrm{COOH}$;
  B – ${\mathrm{CH}}_3{\mathrm{COC}}_2{H}_5$
• D. A – ${\mathrm{CH}}_3\mathrm{COOH}$;
  B – ${\mathrm{CH}}_3{\mathrm{COOC}}_2{H}_5$

Answer 1

The correct option is D A – ${\mathrm{CH}}_3\mathrm{COOH}$;

B – ${\mathrm{CH}}_3{\mathrm{COOC}}_2{H}_5$
Compound A is used as a preservative in pickles, therefore ‘A’ must be ethanoic acid which has a chemical formula ${\mathrm{CH}}_3\mathrm{COOH}$.
Now A, which is basically ethanoic acid, reacts with ethanol to give sweet smeling compound ethyl acetate.
$C_2{H}_5\mathrm{OH}+{\mathrm{CH}}_3\mathrm{COOH}\stackrel{\mathrm{Conc}.H_2{\mathrm{SO}}_4}{\to }{\mathrm{CH}}_3{\mathrm{COOC}}_2{H}_5+H_{2}O$