Answer
See answer below.
Work Step by Step
$X^{m-}$ is the anion released by the ionization of the acid.
First reaction:
$m/2\ Na_2S(aq)+H_mX(aq)\rightarrow m/2\ H_2S(g)+Na_mX(aq)$
Net ionic equation:
$S^{2-}(aq)+2\ H_3O^+(aq)\rightarrow H_2S(g)+2\ H_2O(l)$
Second reaction:
$H_2S(g)+Pb(NO_3)_2(aq)\rightarrow 2\ HNO_3(aq)+ PbS(s)$
Net ionic equation:
$2\ H_2O(l)+H_2S(g)+Pb^{2+}(aq)\rightarrow 2\ H_3O^+(aq)+ PbS(s)$
