${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{N}}_2\mathrm{Cl}$ in presence of $\mathrm{KCN}$ and $\mathrm{CuCN}$ gives an organic compound, which on acid hydrolysis gives $\text{'} \mathrm{X} \text{'}$ The compound $\text{'} \mathrm{X} \text{'}$ may be