Household Cleaners: Chemistry Under the Kitchen Sink

I have recently been asked questions regarding household cleaners, so this entry is designed to answer them as thorough as possible. 

When many people hear the word "chemical" they often picture people in CSI type labs, with fuming beakers, in labs coats and safety glasses, but chemicals are every where. You are made of chemicals, you are dressed in chemicals, and you are eating chemicals. When you consider this much broader definition you can now see how the potential for reaction is everywhere. The main source of chemicals in our homes is generally under kitchen sink: cleansers-that is if you believe in cleaning your house. We can have cleaners for all different types of reasons, which means that the litany of chemicals under your sink can be quite vast (especially if you are a very good friend of mine who treats cleaning her house as a form of exercise and meditative relief-you know who you are) and that means that some of them will be incompatible-or to be more specific they will react. 

Bleach + ammonia = bad! We all have heard this, but why? Household bleach is a 5% solution of sodium hypochlorite, NaOCl, in water.  Window cleaners, like Windex, are made from ammonia: NH3. 

NaOCl + NH3 = NH2Cl + NaOH

NH2Cl-chloramine. This is unstable and explosive. It is also possible to over chlorinate to get NHCl2 and NCl3, which are equally terrible for you. Interesting side note: replacing the chlorine atoms with iodine atoms, it becomes possible to make nitrogen triiodide, NI3. This is a contact explosive and a favourite practical joke among chemists. We use it demos because by touching the stuff with a feather it is possible to make it explode. You can also put it on the underside of a toilet seat, so when someone sits down they are greeted with a large, ear-ring bang. My personal favourite April Fools Day joke is to put it the key holes of doors so that when people insert their key it causes the explosions. (Note: these aren't TNT level structure ruining  explosions, just a loud bang type). 

"Why is ammonia a useful glass cleaner?" Fingerprints are a usual problem on glass. A fingerprint is caused by the oils on your skin, which are made of fatty acids. As the name implies, they are acidic. When the acids react with a base, like ammonia, they are converted to water soluble salts and are washed away. (The free-basing of cocaine hydrochloride uses the same chemical principle to make crack.)

The other household question I got was "why should you where gloves when using CLR?"

CLR removes calcium, lime, and rust. These are all metal based problems and are easily eaten away by an acid. My favourite way of cleaning up calcium blockages in my own lab equipment is using 6 molar hydrochloric acid. A more dilute solution of this is made and packaged and sold to consumers as CLR. But being an acid, it is possible for it to cause burns on your skin, so wearing gloves will protect you skin.