Answer
See answer below.
Work Step by Step
a) $CuCl_2(aq)+H_2S(g)\rightarrow CuS(s)+2\ HCl(aq)$
Precipitation reaction.
b) $H_3PO_4(aq)+3\ KOH(aq)\rightarrow 3\ H_2O(l)+K_3PO_4(aq)$
Acid-base reaction.
c) $Ca(s)+2\ HBr(aq)\rightarrow H_2(g)+CaBr_2(aq)$
Gas-forming and oxidation-reduction reaction.
d) $MgCl_2(aq)+2\ NaOH(aq)\rightarrow Mg(OH)_2(s)+2\ NaCl(aq)$
Precipitation reaction.
