I've read a few articles advising not to mix bleach and ammonia in the same room because it makes chloramine gas. But my boyfriend and I are having an argument - he thinks that since those articles don't specifically say that mixing them in the same room (in our case, our small, poorly-ventilated bathroom) is bad, the only situation in which we shouldn't do this is spraying them directly on the same surface.

I don't see any reason why the chemical reactions producing chloramine gas wouldn't occur if they're mixing in the same room, from our bleach cleaner and glass cleaner spray bottles, though they would be less concentrated. However, he would only trust an answer from a chemistry expert. Please advise!

  • 1
    $\begingroup$ What do you mean by "mixing in the same room" exactly? $\endgroup$
    – Gerhard
    Commented Dec 13, 2015 at 1:29
  • $\begingroup$ First bleach and ammonia will yield chlorine gas. // If you clean the mirror with the ammonia spray and the sink with the bleach spray then you should be fine. However you certainly should not spray both cleaners on the same surface at the same time. $\endgroup$
    – MaxW
    Commented Dec 13, 2015 at 1:45
  • $\begingroup$ MaxW, that is exactly what I was wondering. $\endgroup$
    – nCardot
    Commented Dec 13, 2015 at 3:25
  • 1
    $\begingroup$ And by the way Max W, why wouldn't chlorine gas be formed by mixing them in the air alone? Is there something about the sprays mixing in the air that would make inhibit the reaction? $\endgroup$
    – nCardot
    Commented Dec 13, 2015 at 3:27
  • 1
    $\begingroup$ However the amount of liquid left in the air will be so small that it wouldn't be a problem.[citation needed] $\endgroup$
    – Curt F.
    Commented Dec 13, 2015 at 4:53

2 Answers 2


This information is only for academic and educational purpose only. Please never ever try to mix ammonia and bleach.

Mixing bleach and ammonia is extremely dangerous, since many toxic vapors (nitrogen-chlorine species) will be produced. The primary toxic chemical formed by the reaction is chloramine vapor and hydrazine. (very, very toxic).

The following is the list of chemical species produced by the reaction:

  1. $\ce{NH3}$ = ammonia
  2. $\ce{HCl}$ = hydrochloric acid
  3. $\ce{NaOCl}$ = sodium hypochlorite
  4. $\ce{Cl2}$ = chlorine gas
  5. $\ce{NH2Cl}$ = chloramine
  6. $\ce{N2H4}$ = hydrazine
  7. $\ce{NaCl}$ = sodium chloride or salt (non-toxic)
  8. $\ce{H2O}$ = water (non-toxic)

The bleach decomposes to form hydrochloric acid:

$$\ce{NaOCl → NaOH + HOCl}$$

$$\ce{HOCl → HCl + [O]}$$

And then the ammonia and chlorine gas react to form chloramine, which is released as a vapor:

$$\ce{NaOCl + 2HCl → Cl2 + NaCl + H2O}$$

$$\ce{2NH3 + Cl2 → 2NH2Cl}$$

If ammonia is present in excess, toxic and potentially explosive liquid hydrazine may be formed.

$$\ce{2NH3 + NaOCl → N2H4 + NaCl + H2O}$$


  1. http://chemistry.about.com/od/toxicchemicals/a/Mixing-Bleach-And-Ammonia.htm
  2. http://home.onehowto.com/article/what-happens-when-you-mix-bleach-and-ammonia-7512.html
  • $\begingroup$ Not sure about hydrochloric acid (not mutually stable with ammonia), I would have put ammonium chloride instead. But products $4, 5, 6$ are nasty enough. $\endgroup$ Commented Jan 30, 2017 at 1:42

My story is simpler than other answers. When I was in graduate school one of the cleaning guys told me he was knocked out mixing ammonia and bleach in his cleaning solution.

Bleach itself is best stored (and used) well separated from other household chemicals. Ammonia, acid, organic solvents -- all can react with bleach to give chlorine gas and other dangerous stuff.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.