The rate of a photochemical reaction involving the decomposition of chlorine gas Cl2 is primarily dependent on the intensity of light photon energy rather than temperature. This is because photochemical reactions are initiated by the absorption of light energy, which provides the energy required to break the chemical bonds.In the case of chlorine gas, when it absorbs light energy usually in the ultraviolet region , the Cl2 molecules dissociate into two chlorine atoms Cl :Cl2 + h 2Clwhere h represents the energy of the absorbed photon.However, temperature can still have an indirect effect on the rate of a photochemical reaction. As the temperature increases, the kinetic energy of the molecules also increases, which can lead to more frequent and effective collisions between the molecules and the photons. This can result in a higher probability of the molecules absorbing the light energy and undergoing the photochemical reaction.Additionally, higher temperatures can also affect the equilibrium between the reactants and products in the reaction, which may influence the overall reaction rate. In the case of chlorine gas decomposition, the reaction is endothermic, meaning it absorbs energy. Therefore, increasing the temperature may shift the equilibrium towards the products chlorine atoms , potentially increasing the reaction rate.In summary, while the rate of a photochemical reaction involving the decomposition of chlorine gas is mainly dependent on the intensity of light, temperature can still have an indirect effect on the reaction rate through its influence on molecular kinetic energy and reaction equilibrium.