I am new to this service so please overlook any mistakes.

My question is with regards to free radical substitution. I understand the three step process of the bromination of ethane and what would occur if chlorine was in excess.

I do not however understand what would happen if ethane was in excess. What would occur and what would be the major product produced?

  • 1
    $\begingroup$ You'd definitely get the monobrominated product, but if your ethane was in large excess you'd get practically no yield. $\endgroup$ Commented Mar 29, 2016 at 22:12
  • $\begingroup$ So bromine or chlorine? That's a typo saying chlorine in the middle there, isn't it? $\endgroup$
    – Jan
    Commented Sep 25, 2016 at 19:08

1 Answer 1


If there is an excess of ethane, you would be getting the monosubstituted bromoethane, $\ce{CH3CH2Br}$, as the main product.

When ethane, $\ce{CH3CH3}$, is in excess, for any bromine radical formed, most of the reacting particles around it would be an unreacted ethane molecule (high concentration of $\ce{CH3CH3}$), this means that there is a greater chance of a bromine radical colliding with and reacting with $\ce{CH3CH3}$ to form the monosubstituted bromoethane.

This is in contrast with when bromine is in excess, where the excess of highly reactive bromine radicals mean that most of them react fully with the available ethane molecules to form fully substituted $\ce{CBr3CBr3}$.


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