\(\begin{array}{l}
a)\\
Fe + {H_2}S{O_4} \to FeS{O_4} + {H_2}\\
Ca{(OH)_2} + {H_2}S{O_4} \to CaS{O_4} + 2{H_2}O\\
FeO + {H_2}S{O_4} \to FeS{O_4} + {H_2}O\\
CaC{O_3} + {H_2}S{O_4} \to CaS{O_4} + C{O_2} + {H_2}O\\
F{e_2}{O_3} + 3{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + 3{H_2}O\\
F{e_3}{O_4} + 4{H_2}S{O_4} \to FeS{O_4} + F{e_2}{(S{O_4})_3} + 4{H_2}O\\
Cu{(OH)_2} + {H_2}S{O_4} \to CuS{O_4} + 2{H_2}O\\
Mg + {H_2}S{O_4} \to MgS{O_4} + {H_2}\\
b)\\
2Fe + 6{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + 3S{O_2} + 6{H_2}O\\
2FeO + 4{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + S{O_2} + 4{H_2}O\\
F{e_2}{O_3} + 3{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + 3{H_2}O\\
2FeS{O_4} + 2{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + S{O_2} + 2{H_2}O\\
2F{e_3}{O_4} + 10{H_2}S{O_4} \to 3F{e_2}{(S{O_4})_3} + S{O_2} + 10{H_2}O\\
Cu{(OH)_2} + {H_2}S{O_4} \to CuS{O_4} + 2{H_2}O\\
Mg + 2{H_2}S{O_4} \to MgS{O_4} + S{O_2} + 2{H_2}O\\
2Fe{(OH)_3} + 3{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + 6{H_2}O\\
2Fe{(OH)_2} + 4{H_2}S{O_4} \to F{e_2}{(S{O_4})_3} + S{O_2} + 6{H_2}O\\
C + 2{H_2}S{O_4} \to 2S{O_2} + C{O_2} + 2{H_2}O\\
2NaOH + {H_2}S{O_4} \to N{a_2}S{O_4} + 2{H_2}O
\end{array}\)
