Answer
(a) Nearly neutral
(b) Basic
(c) Acidic
(d) Acidic
Work Step by Step
(a) $NaOH$ is a strong base, and $HBr$ is a strong acid; therefore, this salt is nearly neutral, because both conjugate pairs will not affect the pH.
(b) $KOH$ is a strong base, and $HSO_3^-$ is a weak acid; therefore, this salt is basic.
(c) $NH_3$ is a weak base, and $HNO_2$ is a weak acid. But, if we compare their equilibrium constant for ionization, $HNO_2$ is stronger; therefore, $NH_4NO_2$ is acidic.
(d) $Cr(OH)_3$ is a weak base, and $HNO_3$ is a strong acid; therefore, this salt will create an acidic solution.
