Arrange the following oxyacids of chlorine in increasing order of acid strength: $ ext{HClO}_3$, $\

Question

Arrange the following oxyacids of chlorine in increasing order of acid strength: $	ext{HClO}_3$, $	ext{HClO}_4$, $	ext{HClO}_2$, $	ext{HClO}$

Professor PC Thomas Classes · Answer

The acid strength of oxyacids of the same halogen increases with the increasing oxidation number of the halogen atom. In $	ext{HClO}$, $	ext{HClO}_2$, $	ext{HClO}_3$, and $	ext{HClO}_4$, the oxidation states of chlorine are $+1$, $+3$, $+5$, and $+7$ respectively.
Alternatively, this can be explained by the stability of the conjugate base. The conjugate bases are $	ext{ClO}^-$, $	ext{ClO}_2^-$, $	ext{ClO}_3^-$, and $	ext{ClO}_4^-$. As the number of oxygen atoms increases, the negative charge is delocalized over more oxygen atoms, making the conjugate base more stable. A more stable conjugate base corresponds to a stronger acid.
Therefore, the increasing order of acid strength is: $	ext{HClO} < 	ext{HClO}_2 < 	ext{HClO}_3 < 	ext{HClO}_4$.