Question

Describe the following about halogen family elements:

Oxoacids and their relative oxidising ability

Answer 1

1. Oxoacids of Halogens: Fluorine forms only one oxoacid, hypofluorous acid (HOF), which is unstable. Chlorine, bromine, and iodine form hypohalous (HXO), halous (HXO₂), halic (HXO₃), and perhalic acids (HXO₄).
2. Acid Strength: Acid strength increases with the oxidation state of the halogen: HOCl < HClO₂ < HClO₃ < HClO₄. For the same oxidation state, acid strength decreases down the group: HClO > HBrO > HIO.
3. Oxidising Ability: Oxidising power decreases from hypohalous to halic acids. Perhalates (salts of perhalic acids) are strong oxidisers with order: \[\ce{BrO^-_4 > ClO^-_4 < IO^-_4}\]. Fluorine and its oxoacid are very strong oxidisers.