Question

Which of the following pair of compounds on reactions form a substance having a fruity smell?

• A. ${\text{CH}}_3\text{CHO}$ and ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{COOH}$
• B. ${\text{CH}}_3\text{OH}$ and ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{COOH}$
• C. ${\text{CH}}_3{\text{COCH}}_2$ and ${\text{CH}}_3{\text{CH}}_2\text{OH}$
• D. ${\text{CH}}_3{\text{COCH}}_2$ and ${\text{CH}}_3{\text{CH}}_2\text{CHO}$

Answer 1

The correct option is B ${\text{CH}}_3\text{OH}$ and ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{COOH}$

Esters are compounds having fruity smell. An ester is formed when a carboxylic acid reacts with an alcohol in the presence of conc. ${\text{H}}_2{\text{SO}}_4$. This process is known as esterification.

The reaction of methanol and butanoic acid will an ester called methyl butanoate. The reaction occurs as follows:

${\mathrm{CH}}_3\mathrm{OH}\left(\mathrm{aq}\right)+{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{COOH}\left(\mathrm{aq}\right)\underset{\Delta }{\overset{\mathrm{conc}.H_2{\mathrm{SO}}_4}{\to }}{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{COOCH}}_3\left(\mathrm{aq}\right)+H_{2}O\mathrm{Methanol}\mathrm{Butanoic}\mathrm{acid}\mathrm{Methyl}\mathrm{butanoate}$