Often, one looks at a bottle of bleach and wonders, 'Why shouldn't this be mixed with ammonia?' If you know how dangerous chlorine gas is to humans (it was used as a chemical weapon during World War I and later by Nazi Germany in World War II), this will be very apparent. This entry will tell of a few reactions that can occur when bleach and ammonia are mixed in various proportions - the release of chlorine gas is just one of these. In the following sections, the header will be the name of the most dangerous compound produced in the reaction shown. Please, do not try any of this at home.
Chlorine Gas (Cl2)
That warning is there to protect you. Household bleach has a chemical formula of NaOCl - that is, one atom each of sodium, oxygen, and chlorine. Its chemical name, for the curious, is sodium hypochlorite. Ammonia has a chemical formula of NH3, that is, one atom of nitrogen and three atoms of hydrogen. When these two compounds are combined, the following reaction takes place:
2(parts)NaOCl + 2NH3 --> 2NaONH3 + Cl2.
Do you see that Cl2 on the right hand side there? This means one part chlorine gas, made up of diatomic (two atom) molecules. It also means that the chlorine gas has been liberated from the bleach, and is quite capable of causing you harm when inhaled!
The Pain! The Pain!
To understand the effects chlorine gas has on the body, we first need to understand the chemical properties of chlorine, particularly its valence, or number of chemical bonds chlorine can form. Chlorine is in the seventh of the traditional groups of elements, one before the group of inert gases, which, as their name suggests, are almost completely unreactive. Chlorine has seven electrons in its outer electron shell.
The Octet Rule states that all elements try to fill in their outer electron shell until they have eight electrons. When a chemical has eight electrons in its outer shell, it is then stable. Being so close to having 8 electrons in its outer shell, chlorine is quite desperate to get that one last electron - and will literally rip other atoms apart to do so. This is what happens to your respiratory system when you inhale chlorine gas. The gas tears into your nasal passages, trachea, and lungs by causing massive cellular damage. Obviously, chlorine gas causes a very painful death. Worse than that, it may not quite kill you but leave you with permanent lung damage.
Nitrogen Trichloride (NCl3)
Another potential reaction, which occurs when a greater amount of bleach is added than ammonia, is this:
3NaOCl + NH3 --> 3NaOH + NCl3
That's sodium hydroxide and nitrogen trichloride. Nitrogen trichloride is a very toxic chemical to humans, and even if you did get close enough to ingest it, it would probably explode in your face first, as it is also a very volatile explosive. There is little necessity in explaining why that is bad.
Still another reaction - in three parts this time - can occur, producing hydrazine (N2H4, a component of rocket fuel) if you have more ammonia than bleach:
NH3 + NaOCl --> NaOH + NH2Cl.
These two products then react with ammonia as follows:
NH3 + NH2Cl + NaOH -->N2H4 + NaCl + H2O.
One last reaction occurs to stabilise the reagents:
2NH2Cl + N2H4 --> 2 NH4Cl + N2.
This last equation is of particular interest because of the amount of heat it produces. The heat is so great that it usually leads to an explosion.
As mentioned before, this article mentions some very dangerous chemicals. One should not ever, ever attempt to create the chemicals described above as it could result in injury or even death. Or as stated above, permanent irreversible damage to your health.