Answer Hint: The addition of chlorine to a molecule or a compound is known as chlorination. Chlorine can be added to a compound through addition or substitution. Methane is an organic compound having the chemical formula \[C{H_4}\]. It is the simplest hydrocarbon which is the compound of hydrogen and carbon. Complete step by step answer: Hence option C is correct i.e. substitution. Note: The radical reaction suffers through a major drawback. If the termination of radical does not occur, then the reaction gives a mixture of products. For this reaction there are several products possible like chloromethane, dichloromethane, trichloromethane, and tetrachloromethane. That is why the termination step is very important in radical reaction. If a mixture of methane and chlorine is exposed to a flame, it explodes - producing carbon and hydrogen chloride. This is not a very useful reaction! The reaction we are going to explore is a more gentle one between methane and chlorine in the presence of ultraviolet light - typically sunlight. This is a good example of a photochemical reaction - a reaction brought about by light. \[ CH_4 + Cl_2 \rightarrow CH_3Cl + HCl\] The organic product is chloromethane. One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction. However, the reaction does not stop there, and all the hydrogens in the methane can in turn be replaced by chlorine atoms. Multiple substitution is dealt with on a separate page, and you will find a link to that at the bottom of this page.
The mechanism involves a chain reaction. During a chain reaction, for every reactive species you start off with, a new one is generated at the end - and this keeps the process going. The over-all process is known as free radical substitution, or as a free radical chain reaction.
Cl2 \(\rightarrow\) 2Cl
CH4 + Cl\(\rightarrow\)CH3 + HCl CH3 + Cl2\(\rightarrow\)CH3Cl + Cl
2Cl\(\rightarrow\)Cl2 CH3 + Cl \(\rightarrow\) CH3C l CH3 + CH3\(\rightarrow\)CH3CH3 Contributors
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