28. Solving a chemistry problem

1. The following photochemical reactions are considered:
C6H6Cl2→C6H6Cl HCl;
For the reaction of each variant, the mass of the starting material m(in) and the mass of the product m(prod) are given underlined in the corresponding reaction equation. Electromagnetic radiation with a long wavelength λ and energy E0 is passed through the reactor. The measurements showed that the energy of the transmitted radiation was E. Calculate the quantum yield of the reaction and draw a conclusion about the mechanism of the photochemical reaction (simple, complex).
Reaction 1
m(ref), g 1.8
m(prod), g 0.696
E0, J 39.7
E0,J 16.3
λ, nm 313