To a buffer solution of $C{H}_{3}COOH$ and $C{H}_{3}COONa$, some $HCl$ is added. Then the reaction involved is

In this solution

$C{H}_{3}COOH\rightleftharpoons C{H}_{3}CO{O}^{-}+H^{+}$

$C{H}_{3}COONa\to C{H}_{3}CO{O}^{-}+N{a}^{+}$

Explanation: Upon addition of $HCl$ to the buffer solution the resulting $H^{+}$ ions will produce $C{H}_{3}COOH$

Hence, the correct option is (2) $C{H}_{3}CO{O}^{-}+H^{+}\to C{H}_{3}COOH$