Haloalkanes And Haloarenes

Identify compound \(\mathrm{Y}\) in the following reaction. \(\mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}+\mathrm{Y} \stackrel{\Delta}{\longrightarrow} \mathrm{C}_2 \mathrm{H}_5 \mathrm{CN}\)