The reaction of methane (CH₄) with chlorine (Cl₂) is a substitution reaction where hydrogen atoms in methane are replaced by chlorine atoms. This reaction requires light or heat to initiate.

Here's how you can write the chemical equation:

CH₄ + Cl₂ → CH₃Cl + HCl

This represents the first step of the reaction, where one hydrogen atom is replaced by a chlorine atom. This produces chloromethane (CH₃Cl) and hydrogen chloride (HCl).

However, the reaction doesn't stop there! The reaction can continue, with further substitutions occurring, depending on the conditions:

* Second step: CH₃Cl + Cl₂ → CH₂Cl₂ + HCl (producing dichloromethane)

* Third step: CH₂Cl₂ + Cl₂ → CHCl₃ + HCl (producing trichloromethane, also known as chloroform)

* Fourth step: CHCl₃ + Cl₂ → CCl₄ + HCl (producing tetrachloromethane, also known as carbon tetrachloride)

Overall reaction:

CH₄ + 4Cl₂ → CCl₄ + 4HCl

Important Notes:

* Conditions: The reaction can produce a mixture of chlorinated products, with the proportions depending on the conditions (e.g., amount of chlorine, temperature, and light intensity).

* Mechanism: The reaction proceeds via a free radical mechanism. This involves the formation of highly reactive species called free radicals, which initiate the chain reaction of substitution.

* Applications: This reaction is used industrially to produce various chlorinated hydrocarbons, which have applications as solvents, refrigerants, and in the manufacture of polymers.

Let me know if you have any other questions!