What happens when (Give equations also):
$(i)$ Methane reacts with excess of chlorine in the presence of diffused sunlight.
$(ii)$ Ethanol undergoes combustion.
$(iii)$ Ethyl alcohol reacts with acidified potassium dichromate.

(N/A) $(i)$ Methane reacts with excess chlorine in the presence of diffused sunlight to form carbon tetrachloride and hydrogen chloride:
$CH_{4} + 4Cl_{2} \xrightarrow{\text{Diffused sunlight}} CCl_{4} + 4HCl$
$(ii)$ Ethanol undergoes complete combustion to produce carbon dioxide,water,and energy (heat and light):
$CH_{3}CH_{2}OH + 3O_{2} \longrightarrow 2CO_{2} + 3H_{2}O + \text{Heat and light}$
$(iii)$ Ethyl alcohol (ethanol) is oxidized by acidified potassium dichromate $(K_{2}Cr_{2}O_{7})$ to form ethanoic acid:
$CH_{3}CH_{2}OH + 2[O] \xrightarrow{\text{Acidified } K_{2}Cr_{2}O_{7}} CH_{3}COOH + H_{2}O$