Answer
See answer below.
Work Step by Step
a)$K_2CO_3(aq) +Cu(NO_3)_2(aq) \rightarrow CuCO_3(s)+2\ KNO_3(aq)$
Precipitation reaction
b)$Pb(NO_3)_2(aq) +2\ HCl(aq) \rightarrow PbCl_2(s)+2\ HNO_3(aq)$
Precipitation reaction
c) $MgCO_3(s)+2\ HCl(aq)\rightarrow MgCl_2(aq)+H_2O(l)+CO_2(g)$
Gas-forming reaction