Acetic acid reacts with a sodium compound to release a gas which turns lime water milky. What might be the sodium compound?

The correct options are
C

Sodium carbonate

D

Sodium bicarbonate

Sodium acetate doesn’t react with acetic acid

but reduces the concentration of $H^{+}$ ions.
Acetic acid reacts with sodium hydroxide to

give a salt like all neutralisation reactions as

acetic acid is an acid and sodium hydroxide is a

strong base.

$C{H}_{3}COOH+NaOH\to C{H}_{3}COONa+H_{2}O$

Acetic acid reacts with carbonates or

hydrogen carbonates to give corresponding salts,

water and carbon dioxide. Carbon dioxide is the

gas that turns lime water milky.

$2C{H}_{3}COOH+N{a}_{2}C{O}_3\to 2C{H}_{3}COONa+H_{2}O+C{O}_2$
$C{H}_{3}COOH+NaHC{O}_3\to C{H}_{3}COONa+H_{2}O+C{O}_2$
Hence the sodium compound can either be a

sodium carbonate or a sodium bicarbonate.