Question: How do you neutralize acids?

Ian Cade answered on 7 Nov 2014:

Acids are compounds that can behave as a source of ‘protons’ (Bronsted acids) or compounds that can accept a pair of electrons (Lewis acids) -it may not seem like it but these two properties are quite closely related.

So, to ‘neutralise an acid you just have to stop these behaviours, either:

1) add a base (which will bind to the acidic proton(s), taking it from the acid – the acid can’t donate its proton(s) more than once)

2) add a compound that can donate a pair of electrons (as before, the acid once it has accepted a pair(s) of electrons it can accept any more… so is no longer an acid)

A very simple experiment you can do is to try to neutralise vinegar or lemon juice with bicarbonate of soda (baking soda). The acids in vinegar and lemons are acids because they can donate protons easily, bicarbonate of soda is able to accept these protons (in doing so it looses carbon dioxide and ‘fizzes’). So you can neutralise vinegar (or lemon juice) by adding enough bicarbonate of soda until the mixture stops fizzing (i.e. there are no more acidic protons left to react). In this case, since the ingredients you are using are all perfectly edible you could try tasting the vinegar (or lemon juice) before and after ‘neutralising’ it.. there should be a change!

IMPORTANTLY… though common in the past (150 years ago or so), tasting your reactions is no longer considered a sensible thing to do… mainly due to the possibility of poisoning yourself. So, with the exception of the example I gave above (which should be quite harmless), DO NOT get into the habit of tasting your science! (for example, despite sounding similar, washing soda and baking soda are not at all the same thing, baking soda is probably fine to taste, washing soda is not).