When I asked my teacher whether all disproportionation reactions are decomposition reactions, he stated the following reaction:

$$ \ce{4 KClO3 -> 3 KClO4 + KCl} $$

and said that this isn't a decomposition reaction and that it is a hydrolysis reaction. How is this not a decomposition reaction as the definition of a decomposition reaction is the splitting of a single reactant into multiple products. I see the same happening here, the singular reactant ($\ce{KClO4}$) is splitting into multiple products ($\ce{KClO4}$, $\ce{KCl}$). And also how is this a hydrolysis reaction as I see no $\ce{H2O}$ molecule taking part in it. It would be great if you answer with some proper explanation to help me understand.

  • 2
    $\begingroup$ decomposition implies a more complex thing falls apart into more less complex things. kclo4 is kclo3 plus another atom so it's is the opposite of decomposition. but kcl is less complex so overall it's neither decomposition nor synthesis. that's what we call disproportionation $\endgroup$
    – Francis L.
    May 31, 2021 at 13:02
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    – Buttonwood
    May 31, 2021 at 13:02
  • $\begingroup$ Unless IUPAC says something else, that can be a decomposition reaction, at least the decomposition of the solid lattice of the starting salt. But could also be hydrolysis or whatever. I would say one named it in the more useful way giving the context. In fact, you know it is a disproportionation. An internal example of the latter? Perhaps in organic chemistry. I would wait other users for this point, but I am pretty sure the hypothetical reaction(s) would have a better representative name, again. $\endgroup$
    – Alchimista
    May 31, 2021 at 13:03
  • $\begingroup$ $\ce{KClO3 + O -> KClO4}$ does not seem to be to be decomposition. $\endgroup$
    – Poutnik
    May 31, 2021 at 13:19
  • $\begingroup$ (1) If you talk about decomposition, then this is a decomposition reaction: $\ce{2KClO3 -> 2KCl + 3O2}$. (2) The reaction you mentioned is not hydrolysis because there is no water involved. $\endgroup$ Jun 1, 2021 at 2:46

1 Answer 1


As the comments say, in the reaction, $\ce{KClO_{3}}$ turns into $\ce{KClO_{4}}$ which is not decomposition as $\ce{KClO_{4}}$ has an extra $\ce{O}$ molecule. Water is not involved so, it is not hydrolysis either. So, we can conclude that all disproportionation reactions are not decomposition reactions.


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