Translate the following statements into chemical equations and then balance them.
$(a)$ Hydrogen gas combines with nitrogen to form ammonia.
$(b)$ Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
$(c)$ Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
$(d)$ Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
$(a)$ $3 H _{2(g)}+ N _{2(g)} \longrightarrow 2 NH _{3(g)}$
$(b)$ $2 H _{2} S _{( g )}+3 O _{2( g )} \longrightarrow 2 H _{2} O _{(l)}+2 SO _{2( g )}$
$(c)$ $3BaC{{l}_{2(aq)}}+A{{l}_{2}}{{\left( S{{O}_{4}} \right)}_{3(aq)}}$ $\to 2AlC{{l}_{3\left( aq \right)}}+3BaS{{O}_{4(s)}}$
$(d)$ $2 K _{(s)}+2 H _{2} O _{(l)} \longrightarrow 2 KOH _{(aq)}+ H _{2(g)}$
Balance the following chemical equations.
$(a)$ $HNO _{3}+ Ca ( OH )_{2} \longrightarrow Ca \left( NO _{3}\right)_{2}+ H _{2} O$
$(b)$ $NaOH + H _{2} SO _{4} \longrightarrow Na _{2} SO _{4}+ H _{2} O$
$(c)$ $NaCl + AgNO _{3} \longrightarrow AgCl + NaNO _{3}$
$(d)$ $BaCl _{2}+ H _{2} SO _{4} \longrightarrow BaSO _{4}+ HCl$
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
A shiny brown coloured element $‘X’$ on heating in air becomes black in colour. Name the element $‘X’$ and the black coloured compound formed.
Explain the "Oxidation'' in terms of gain or loss of oxygen with two examples.
Why do we apply paint on iron articles ?