Answer
(a) Acidic.
(b) pH neutral.
(c) Basic.
Work Step by Step
(a) $NO{_3}^-$ does not hydrolyze (Conjugate pair of a strong acid)
$CH_3N{H_3}^+$ does (Conjugate acid of a weak base).
Therefore, the solution will be acidic.
(b)$I^-$ does not hydrolyze (Conjugate pair of a strong acid)
$Na^+$ does not either (Conjugate pair of a strong base).
Neither $Na^+$ nor $I^-$ hydrolyzes: Neutral solution.
(c) $Na^+$ does not hydrolyze (Conjugate pair of a strong base)
$N{O_2}^-$ does (Conjugate base of a weak acid).
The solution will be basic.
