1.
Consider the following reactions:

X HCl, Anhyd. AlCl3,C2H5Cl\xrightarrow{\text{HCl, Anhyd. AlCl}_3, \text{C}_2\text{H}_5\text{Cl}} Addition product (D)

Y Anhyd. ZnCl2/HCl\xrightarrow{\text{Anhyd. ZnCl}_2 / \text{HCl}} Substitution product

Y can be converted to X on heating with at temperature: