Question

Giving suitable explanation, arrange oxoacids of chlorine in the increasing order of their acid strength.

Answer 1

1. Chlorine forms four oxoacids: hypochlorous acid (HOCl), chlorous acid (HClO₂), chloric acid (HClO₃), and perchloric acid (HClO₄).
2. Acid strength increases with the number of oxygen atoms or the oxidation state of chlorine.
3. The order of acid strength is:
   HOCl < HClO₂ < HClO₃ < HClO₄
4. This is because the stability of the conjugate base anion increases with more oxygen atoms, as negative charge is better delocalised by resonance. Hence, the anion stability order is \[\ce{ClO- < ClO^-_2 < ClO^-_3 < ClO^-_4}\], which results in increasing acid strength.