Write a balanced chemical equation for each of the following reactions and also classify them.
$(a)$ Iron $(III)$ oxide on heating with carbon monoxide gas reacts to form solid iron and liberates carbon dioxide gas.
$(b)$ Hydrogen sulphide gas reacts with oxygen gas to form solid sulphur and liquid water.

(N/A) The balanced chemical equation is: $Fe_{2}O_{3}(s) + 3CO(g) \longrightarrow 2Fe(s) + 3CO_{2}(g)$.
This is a redox reaction because iron $(III)$ oxide is reduced to iron,and carbon monoxide is oxidized to carbon dioxide.
$(b)$ The balanced chemical equation is: $2H_{2}S(g) + O_{2}(g) \longrightarrow 2S(s) + 2H_{2}O(l)$.
This is a redox reaction because hydrogen sulphide is oxidized to sulphur,and oxygen is reduced to water.