In the substitution reaction of methane (CH4) with chlorine (Cl2) under UV light, what is the first product formed?

The first product formed in the substitution reaction of methane with chlorine is Chloromethane. This reaction occurs in the presence of ultraviolet light or sunlight, which provides the energy required to break the chlorine-chlorine bond to start the process. It is a free-radical substitution reaction where one hydrogen atom of methane is replaced by one chlorine atom, represented by: CH4 + Cl2 → CH3Cl + HCl. If chlorine is in excess, the reaction continues to replace the remaining hydrogen atoms, eventually producing dichloromethane, trichloromethane, and finally carbon tetrachloride.