Question

The correct order of decreasing acid strength among the following acids is

• A. $HClO > HBrO > HIO$
• B. $HIO > HBrO > HClO$
• C. $HBrO > HClO > HIO$
• D. $HClO > HIO > HBrO$

Answer 1

Answer: (A)

$HClO > HBrO > HIO$

Answer 2

Acid strength of oxoacids of different halogens having same oxidation state decreases with the increase in atomic number i.e., $HOCl > HOBr > HOI$. As the electronegativity of the halogen decreases from $Cl$ to $I$, the shared pair of electrons o f the oxygen - halogen bond moves closer and closer torwards the oxygen atom. As a result, $O - H$ bond breaks most readily in $HOCl$ and least readily in $HOI$