Question

Is ${\mathbf{HClO}}_{\mathbf{2}}$or ${\mathbf{HClO}}_{\mathbf{3}}$ a stronger acid?

Answer 1

1. Chloric acid(${\mathbf{HClO}}_{\mathbf{3}}$)is stronger than Chlorous acid(${\mathbf{HClO}}_{\mathbf{2}}$ )_, Because it has more oxygen atoms.
2. In addition to the oxygen atom, which is bonded to the chlorine atom alone, chlorous and chloric acid each have one, two additional double bonds with oxygen atoms.
3. Because oxygen is more electronegative than chlorine, oxygen atoms that are doubly bonded to it will remove electron density from the chlorine atom.
4. The $\mathbf{C}\mathbf{=}\mathbf{O}$ bond of chlorous acid removes the electron density from the negatively charged oxygen atom in the conjugate base, making the conjugate base more stable and increasing the acidity of the solution Because chloric acid has two $\mathbf{Cl}\mathbf{=}\mathbf{O}$ bonds, it will have a more stable conjugate base than chlorous acid because there will be two oxygen atoms pulling electrons from the negatively charged oxygen atom.
5. Therefore, chloric acid will have a higher acid strength than chlorous acid.

Hence, ${\mathbf{HClO}}_{\mathbf{3}}$is stronger than ${\mathbf{HClO}}_{\mathbf{2}}$.