Explain why the ionization constant, \({K_a}\), for\({H_2}S{O_4}\) is larger than the ionization constant for \({H_2}S{O_3}\).

\({K_a}\)(acidity constant or acid-ionization constant) is a quantitative measure of an acid's strength in solution. In the context of acid-base processes, it is the equilibrium constant for a chemical reaction known as dissociation.

\({K_a}\)is the constant of dissociation of an acid. It is calculated as

\(HA(aq) \to {H^ + }(aq) + {A^ - }(aq)\)

\({K_a} = \frac{{c\left( {{H^ + }} \right) \times c\left( {{A^ - }} \right)}}{{c(HA)}}\)

If the constant is bigger, the acid is stronger, as it means greater dissociation. If the strong acid has stable conjugated base, it does not react with conjugated acid to produce the reactant. Weak acid does not dissociate as conjugated base is not stable and reacts with conjugated acid to produce the reactant. From the same initial concentrations of weak and strong acids, there are more protons. pH is lower in strong acids and higher in weak acids.

\({H_2}S{O_4}\)has larger \({K_a}\) and so it is a stronger acid than \({H_2}S{O_3}\)\(\left( {HSO_4^ - } \right.\)is more stable conjugated base than \(\left. {HSO_3^ - } \right)\).