Friday, September 12, 2008

Bleach And Ammonia

I researched this to help my daughter with a project she was working on, and want to save the information somewhere so I can reference it wherever I may be. Mixing bleach and ammonia is dangerous, don't try this at home.

Bleach and Ammonia
There are several ways household ammonia and bleach can react. All of them are dangerous. Bleach is about 5% sodium hypochlorite (NaOCl), and household ammonia is a solution of 5-10% ammonia (NH3) in water (H2O).

Reaction 1
If you have more ammonia than bleach, the ammonia reacts directly with the bleach to form hydrazine (N2H4), a component in rocket fuel, which, in addition to being extremely poisonous, can burn even in the absence of air. It explodes on contact with rust.

2NH3 + NaOCl -> N2H4 + NaCl + H2O

Reaction 2
If you have more bleach than ammonia, the bleach hydrolyzes (breaks down by reaction with water) into sodium hydroxide (NaOH) and hypochlorous acid (HOCl), which in turn decomposes into chlorine gas (Cl2) and nascent oxygen (both poisonous). The chlorine gas in turn reacts with the ammonia to form chloramines, also very poisonous.

NaOCl + H2O -> NaOH + HOCl
HOCl -> HCl + O (monatomic oxygen)
NaOCl + 2HCl -> Cl2 + NaCl + H2O
2NH3 + Cl2 -> 2NH2Cl (chloramine)
4NH3 + 2Cl2 -> 2NHCl2 (dichloramine)
6NH3 + 3Cl2 -> 2NCl3 (trichloramine or nitrogen trichloride)