Answer
See answer below.
Work Step by Step
a) Reaction: $HNO_2(aq)+NaOH(aq)\rightarrow NaNO_2(aq)+H_2O(l)$
Net ionic: $HNO_2(aq)+OH^-(aq)\rightarrow NO_2^-(aq)+H_2O(l)$
The weak acid doesn't ionize completely.
b) Reaction: $Ca(OH)_2(aq)+2\ HCl(aq) \rightarrow BaCl_2(aq)+2\ H_2O(l)$
Net ionic: $H_3O^{+}(aq)+OH^{-}(aq)\rightarrow 2\ H_2O(l)$
