Answer
(a) Solution A has the higher percent ionization and the higher pH.
Work Step by Step
Solution B has a higher initial concentration of $HNO_2$ than solution A.
With higher initial concentration of acid, we get more concentration of $H_3O^+$.
With lower initial concentration of acid, we also get a higher percent ionization due to Le Chatelier's Principle, and the inverse is also true.
Thus, Solution B has a lower pH and lower percent ionization, and Solution A has the opposite.
