Question

Which one of the following is conjugate acid of water in the reaction? $H_{2}S{O}_4+H_{2}O{H}_3{O}^{+}+HS{O}_4^{-}$

• A. $H_{2}O$
• B. $H_3{O}^{+}$
• C. $S{O}_4^{2-}$
• D. $HS{O}_4^{-}$

Answer 1

Answer: (B)

$\underset{aci{d}_1}{H_{2}S{O}_4}+\underset{bas{e}_2}{H_{2}O}\underset{aci{d}_2}{H_3{O}^{+}}+\underset{bas{e}_1}{HS{O}_4^{-}}$ In the above reaction, $H_{2}S{O}_4$ lose a proton $(H^{+})$ which is gain by $H_{2}O$ , hence $H_{2}S{O}_4$ is an acid and $H_{2}O$ is base. If this reaction is reversible $H_3{O}^{+}$ losses a proton which is accepted by $HS{O}_4^{-}$ , so $H_3{O}^{+}$ is an acid and $HS{O}_4^{-}$ is base. So, conjugate base of $H_{2}S{O}_4$ is $HS{O}_4^{-}$ and conjugate acid of $H_{2}O$ is $H_3{O}^{+}$ .