What happens when hydrogen gas is passed over heated copper oxide $(CuO)$?

Write balanced chemical equations for the following reactions:
$(i)$ Calcium carbonate on reaction with hydrochloric acid gives calcium chloride,water and carbon dioxide.
$(ii)$ Nitrogen reacts with hydrogen under pressure to form ammonia.
$(iii)$ Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.

The coating formed on the metals such as iron, silver, and copper after corrosion will be:

Which of the following are combination reactions?
$(i)$ $2 KClO_{3} \xrightarrow{\text{Heat}} 2 KCl + 3O_{2}$
$(ii)$ $MgO + H_{2}O \longrightarrow Mg(OH)_{2}$
$(iii)$ $4 Al + 3O_{2} \longrightarrow 2 Al_{2}O_{3}$
$(iv)$ $Zn + FeSO_{4} \longrightarrow ZnSO_{4} + Fe$

Balance the following chemical equations and identify the type of chemical reaction.
$(a)$ $TiCl_4(l) + Mg(s) \to Ti(s) + MgCl_2(s)$
$(b)$ $CaO(s) + SiO_2(s) \to CaSiO_3(s)$
$(c)$ $H_2O_2(l) \xrightarrow{UV} H_2O(l) + O_2(g)$

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.