What happens when 
(i) n-butyl chloride is treated with alcoholic KOH, 
(ii) bromobenzene is treated with Mg in the presence of dry ether, 
(iii) chlorobenzene is subjected to hydrolysis, 
(iv) ethyl chloride is treated with aqueous KOH, 
(v) methyl bromide is treated with sodium in the presence of dry ether,

(I) When n – butyl chloride is treated with alcoholic KOH, the formation of but – l – ene takes place. This reaction is a dehydrohalogenation reaction.

(II)  When bromobenzene is treated with Mg in the presence of dry ether, phenyl magnesium bromide is formed.

(III) Chlorobenzene does not undergo hydrolysis under normal conditions. However, it undergoes hydrolysis when heated in an aqueous sodium hydroxide solution at a temperature of 623 K and a pressure of 300 atm to form phenol.

(IV) When ethyl chloride is treated with aqueous KOH, it undergoes hydrolysis to form ethanol.

(V) When methyl bromide is treated with sodium in the presence of dry ether, ethane is formed. This reaction is known as the Wurtz reaction.