Accepting the definition that an acid is a proton donor,the acid in the following reaction $NH_3 + H_2O \to NH_4^+ + OH^-$ is

Which species acts as an acid in the reaction $CH_{3}COOH_{(aq)} + H_{2}O_{(l)} \rightleftharpoons H_{3}O^{+}_{(aq)} + CH_{3}COO^{-}_{(aq)}$?

Which of the following is known as the hydronium ion?

If $pK_b$ of a base is $5$,then $K_a$ of its conjugate acid will be

Which one of the following compounds will liberate $CO_{2}$ when treated with $NaHCO_{3}$?

The species: $H_{2}O$,$HCO_{3}^{-}$,$HSO_{4}^{-}$,and $NH_{3}$ can act both as Bronsted acids and bases. For each case,give the corresponding conjugate acid and base.