Answer
See answer below.
Work Step by Step
a) $NiCO_3(s)+H_2SO_4(aq)\rightarrow NiSO_4(aq)+H_2O(l)+CO_2(g)$
Gas-forming reaction.
b) $Co(OH)_2(aq)+2\ HBr(aq) \rightarrow CoBr_2(aq)+2\ H_2O(l)$
Acid-base reaction.
c) $AgCH_3CO_2(aq)+NaCl(aq) \rightarrow AgCl(s)+NaCH_3CO_2(aq)$
Precipitation reaction.
d) $NiO(s)+CO(g)\rightarrow Ni(s)+CO_2(g)$
Oxidation-reduction reaction.
