While studying alkanes, I found this written in my book:

Fluoridation can be achieved without violence when alkane is treated with fluorine diluted with an inert gas, or by the action of inorganic fluorides like $\ce{AsF3}$, $\ce{SbF3}$, $\ce{AgF}$, $\ce{HgF2}$, $\ce{Hg2F2}$, etc., or by use of bromo or iodo derivatives.

The picture is given below for clarification:

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Inert gases are chemically inactive, except xenon and radon, which are radioactive and may form some compounds.

How do the non-radioactive inert gases help in reducing the violence of fluorination? If I put a certain volume of fluorine and an alkane in a jar for reaction, then even if inert gases are present, they won't react. What is their role?


1 Answer 1


Let's say the gas mixture has something like 10:1 molecules ratio of inert gas : fluorine. The alkanes in the gas would have 10 times more chance of colliding with an inert gas molecule as compared to a fluorine molecule. This reduces the rate at which alkanes and fluorine react together, making the reaction a lot safer (fluorination is highly exothermic to the point where it can be explosive).

The inert gases are basically a necessity, without which it's impossible to do this reaction safely and responsibly.

  • 5
    $\begingroup$ The keyword here is dilution ;) $\endgroup$ Sep 28, 2017 at 5:08
  • 1
    $\begingroup$ Damn @Martin you answered that question with one word! $\endgroup$ Sep 28, 2017 at 10:57

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