$(a)$ Complete the following equations:
$(i)$ $CH_4 + 2O_2 \longrightarrow CO_2 + 2H_2O + \text{Heat} + \text{Light}$
$(ii)$ $CH_3COOH + C_2H_5OH \xrightarrow{\text{Acid}} CH_3COOC_2H_5 + H_2O$
$(iii)$ $CH_3CH_2OH \xrightarrow[\text{443 K}]{\text{Conc. } H_2SO_4} CH_2=CH_2 + H_2O$

(A) $(i)$ Combustion of methane in excess oxygen produces carbon dioxide, water, heat, and light: $CH_4 + 2O_2 \longrightarrow CO_2 + 2H_2O + \text{Heat} + \text{Light}$.
$(ii)$ Esterification reaction between ethanoic acid and ethanol in the presence of an acid catalyst produces ethyl ethanoate (ester) and water: $CH_3COOH + C_2H_5OH \xrightarrow{\text{Acid}} CH_3COOC_2H_5 + H_2O$.
$(iii)$ Dehydration of ethanol using concentrated sulfuric acid at $443 \text{ K}$ produces ethene and water: $CH_3CH_2OH \xrightarrow[\text{443 K}]{\text{Conc. } H_2SO_4} CH_2=CH_2 + H_2O$.