Carboxylic Acids and their Derivatives 1 Question 2
3. The compound that does not liberate $\mathrm{CO}_{2}$, on treatment with aqueous sodium bicarbonate solution, is
(2013 Adv.)
(a) benzoic acid
(b) benzenesulphonic acid
(c) salicylic acid
(d) carbolic acid (Phenol)
Show Answer
Answer:
Correct Answer: 3. (c)
Solution:
- PLAN $\mathrm{NaHCO}{3} \rightleftharpoons \mathrm{Na}^{+}+\mathrm{HCO}{3}^{-}$
$\mathrm{HCO}{3}^{-}$is decomposed by acid releasing $\mathrm{CO}{2}$
$\mathrm{HCO}{3}^{-}+\mathrm{H}^{+} \longrightarrow \mathrm{H}{2} \mathrm{O}+\mathrm{CO}_{2}$
If acid is stronger than $\mathrm{HCO}{3}^{-}$then $\mathrm{CO}{2}$ is released. Phenol is less acidic and thus does not liberate $\mathrm{CO}{2}$ with $\mathrm{NaHCO}{3}$.
