Acid dissociation constant is a measure of strength of a particular acid in a solution. When in the solution, an acid tends to dissociate into ions. Ka value determines how 'capable' that certain acids to dissociates into ions. Strong acids dissociate completely while weak acid (HA) partially dissociates thus forming equilibrium with the solution.
The equilibrium can be written as:
`HA <=> H^(+) + A^(-)`
HA = weak acid
`K_a = ([H^(+)][A^(-)])/([HA])`
Having said that, the larger the Ka value, the stronger the acid. Therefore the answer would be A) HClO2 Ka =1.1 x 10^-2.