A Level Radical Reactions – Propagation Steps

Go back to Synthesis of Chloroalkanes overview

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The second step is propagation, in this step free radical species react with neutral molecules creating new free radicals in a chain reaction.

If the chlorine radicals are in excess the hydrogen atoms will eventually all be replaced making CCl₄, if the methane atoms are in excess the chlorine will be used up quickly giving CH₃Cl as the main product- this is the mostly the case, but it could be worth remembering this for your exam.