Complete the following reactions :
(i) \( C _{6} H _{6} \stackrel{ Cl _{2} / Fe }{\longrightarrow} X \underset{\text { Pyridine }}{\stackrel{ CuCN }{\longrightarrow}} Y \stackrel{ H ^{+}, H _{2} O }{\longrightarrow} \)
(ii) \( C _{2} H _{4} \stackrel{ HBr }{\longrightarrow} X \stackrel{\text { aq. } KOH }{\longrightarrow} Y \stackrel{ 1 , NaOH }{\longrightarrow} Z \)
(iii) \( CH _{3} CH _{2} Br \stackrel{ AgCN }{\longrightarrow} A \)
(iv) 3 -ethylpent-2-ene \( \stackrel{ Br _{2} / H _{2} O }{\longrightarrow} B \)
