Answer
See answer below.
Work Step by Step
a) $MnCl_2(aq)+Na_2S(aq)\rightarrow MnS(s)+2\ NaCl(aq)$
Precipitation reaction.
$Mn^{2+}(aq)+S^{2-}(aq)\rightarrow MnS(s)$
b) $K_2CO_3(aq)+ZnCl_2(aq)\rightarrow ZnCO_3(s)+2\ KCl(aq)$
Precipitation reaction.
$Zn^{2+}(aq)+CO_3^{2-}(aq)\rightarrow ZnCO_3(s)$
