Write the balanced equation for the following chemical reactions.
$(i)$ Hydrogen $+$ Chlorine $\to $ Hydrogen chloride
$(ii)$ Barium chloride $+$ Aluminium sulphate $\to $ Barium sulphate $+$ Aluminium chloride
$(iii)$ Sodium $+$ Water $\to $ Sodium hydroxide $+$ Hydrogen
$(i)$ $H _{2(g)}+ Cl _{2(g)} \longrightarrow 2 HCl _{(g)}$
$(ii)$ $3 BaCl _{2(s)}+ Al _{2}\left( SO _{4}\right)_{3(s)} \longrightarrow 3 BaSO _{4(s)}+2 AlCl _{3(s)}$
$(iii)$ $2 Na _{(s)}+2 H _{2} O _{(i)} \longrightarrow 2 NaOH _{(a q)}+ H _{2(g)}$
What is the difference between displacement and double displacement reactions ? Write equations for these reactions.
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
Explain the "Reduction'' in terms of gain or loss of oxygen with two examples.
Identify the substances that are oxidised and the substances that are reduced in the following reactions.
$(i)$ $4 Na ( s )+ O _{2}( g ) \rightarrow 2 Na _{2} O ( s )$
$(ii)$ $CuO ( s )+ H _{2}( g ) \rightarrow Cu ( s )+ H _{2} O ( l )$
Explain the ''Corrosion'' terms with one example.