The effect of varying light intensities on the rate of the photochemical reaction between chlorine and methane can be understood by examining the reaction mechanism and the role of light in the process. The reaction between chlorine Cl2 and methane CH4 is a photochemical reaction, meaning that it requires light energy to proceed. The overall reaction can be represented as:CH4 + Cl2 CH3Cl + HClThis reaction occurs through a series of steps, with the initiation step being the dissociation of chlorine molecules into chlorine atoms when they absorb light energy:Cl2 + h 2Cl h represents light energy The chlorine atoms generated in the initiation step can then react with methane molecules to form methyl radicals CH3 and hydrogen chloride HCl :Cl + CH4 CH3 + HClThe methyl radicals can further react with chlorine molecules to form chloromethane CH3Cl and another chlorine atom:CH3 + Cl2 CH3Cl + ClThe chlorine atoms generated in the last step can then react with more methane molecules, propagating the chain reaction.Now, let's consider the effect of varying light intensities on the rate of this photochemical reaction. The initiation step, which involves the dissociation of chlorine molecules into chlorine atoms, is directly dependent on the intensity of light. As the light intensity increases, more chlorine molecules will absorb the light energy and dissociate into chlorine atoms. This, in turn, increases the concentration of reactive chlorine atoms, leading to a higher rate of reaction between chlorine and methane.Conversely, when the light intensity decreases, fewer chlorine molecules will dissociate into chlorine atoms, resulting in a lower concentration of reactive chlorine atoms and a slower reaction rate.In summary, the rate of the photochemical reaction between chlorine and methane is directly proportional to the intensity of light. Higher light intensities will increase the reaction rate, while lower light intensities will decrease the reaction rate.