Why do we use chemicals as cleaning supplies?

We have seen how chemists can make better cleaning molecules than soap by changing part of the molecule so that it can dissolve in hard water. We use other chemicals in cleaning products to help in other ways.

We use bleach to remove stains and kill germs. Bleach releases oxygen, which reacts with the stain or the germ. In effect, it slowly burns them. One kind of bleach is hydrogen peroxide, which can bleach clothes and disinfect cuts and scrapes, but is also used to bleach hair.

Phosphoric acid is added to some cleaning products to dissolve hard water films from glass and metal surfaces. It removes lime scale from coffee pots by dissolving the calcium and magnesium compounds left behind as hard water is boiled. Phosphoric acid is a strong acid, but in dilute form it is added to cola drinks to give them a tart taste. Acids taste sour.

Phosphoric acid – cleans hard water deposits from glass

Ammonium hydroxide is a strong alkali, and reacts with fats and oils in much the same way as lye does, forming water soluble soap. It is used in glass cleaning products to remove grease and oils from windows.

Ammonium hydroxide – a strong alkali for cleaning glass

Alcohols dissolve grease and fats, and one alcohol, isopropanol, is used to remove grease from skin and to disinfect the skin (it is sometimes called rubbing alcohol). It is added to window cleaners to help remove oils and grease.