Question

73. Give the corresponding functional isomer of the product formed when ethanol is treated with ethanoic acid.

• A. propanoic acid
• B. ethyl ethanoate
• C. butanoic acid
• D. butanone

Answer 1

The correct option is C

butanoic acid

Explanation of correct option:

Option (C):

• Esterification is the reaction in which acid reacts with alcohol to form the corresponding ester.
• When Ethanol $\left({\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\right)$ is treated with Ethanoic acid $\left({\mathrm{CH}}_3\mathrm{COOH}\right)$, Ethyl ethanoate $\left({\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\right)$ and water $\left({\mathrm{H}}_2\mathrm{O}\right)$ are formed.
• The reaction involved is: ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}+{\mathrm{CH}}_3\mathrm{COOH}\to {\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5+{\mathrm{H}}_2\mathrm{O}$
• Functional isomers are the isomers having the same molecular formula but different functional groups.
• The functional group isomer of Ethyl acetate is Butanoic acid $\left({\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{COOH}\right)$.

Explanation of incorrect options:

Option (A): The molecular formula of Propanoic acid is ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}$. It is not the functional isomer of ethyl ethanoate because its molecular formula is different.

Option (B): The molecular formula of Ethyl ethanoate is ${\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5$. It is the same product formed during the esterification reaction.

Option (D): The molecular formula of Butanone is ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COCH}}_3$. It is not the functional isomer of ethyl ethanoate because its molecular formula is different.

Hence, option (C) is correct.