$[Nu^- = (1) PhO^- , (2) AcO^-, (3) HO^-, (4) CH_3O^-]$
$(i)$ ${C_6}{H_5}{N^ + } \equiv NC{l^ - }$ $(ii)$ ${C_6}{H_5}{N^ + } \equiv N$ $(iii)$ ${{\overset{\centerdot }{\mathop{C}}\,}_{6}}{{H}_{5}}$ $(iv)$ $C_6H_5Cl$