Question

Discuss the following property and its variation with reference to the elements of group 17:

Acidic nature of oxoacids

Answer 1

1. The oxoacids of halogens have acidic protons, as hydrogen is attached to oxygen, which is bonded to halogen atoms.
2. Acidic strength depends on the oxidation state of the halogen; a higher oxidation state means more oxygen atoms, increasing acidity.
3. Acid strength increases in the order hypohalous acid < halous acid < halic acid < perhalic acid.
4. Acidic strength decreases down the group for a given oxidation state because the electronegativity of the halogen decreases (F > Cl > Br > I).
5. For example, in hypohalous acids, acid strength is HClO > HBrO > HIO.
6. The overall trend of acidic strength of oxoacids increases with increasing oxidation number of halogen and decreases down the group.