The number of chlorine atoms present in the organic products X and...

Reaction 1 is an electrophilic aromatic substitution. Benzene reacts with excess chlorine in the presence of anhydrous $\text{AlCl}_3$ (a Lewis acid) to form hexachlorobenzene ($\text{C}_6\text{Cl}_6$).

$\text{C}_6\text{H}_6 + 6\text{Cl}_2 \xrightarrow[\text{dark, cold}]{\text{Anhydr. AlCl}_3} \text{C}_6\text{Cl}_6 + 6\text{HCl}$

The organic product X is hexachlorobenzene, which contains $6$ chlorine atoms.

Reaction 2 is a free radical addition reaction. Benzene reacts with chlorine in the presence of UV light to form benzene hexachloride ($\text{C}_6\text{H}_6\text{Cl}_6$), also known as gammaxene or lindane.

$\text{C}_6\text{H}_6 + 3\text{Cl}_2 \xrightarrow[500\ \text{K}]{\text{UV}} \text{C}_6\text{H}_6\text{Cl}_6$

The organic product Y is benzene hexachloride, which contains $6$ chlorine atoms.

Therefore, the number of chlorine atoms in both X and Y is $6$.

Answer: $6$ and $6$