The amount of detail needed depends on exactly which part of the course you are on. Someone aiming for the higher level of the Further Chemistry course would need all of this. Check with you specification to find out exactly what you require.

 Acids are hydrogen ion donors. When they react, they release H⁺ ion(s).

Bases neutralise acids. They are hydrogen ion acceptors. When they react, they accept H⁺ions.

Some bases are known as alkalis. They contain the OH^-ion and are soluble in water.

Strong acids are totally dissociated in water. This means that for hydrochloric acid (HCl) all of the HCl molecules break down to give H⁺ and Cl^- ions. There is no HCl left.

Weak acids are partly dissociated in water. This means that for ethanoic acid (CH₃COOH) some of the CH₃COOH molecules break down to give CH₃COO^- and H⁺ but some remain as CH₃COOH. This is nothing to do with the CH₃ bit not changing, because these hydrogen are never released. The important thing is that some of the molecules that release the hydrogen atoms that can be released as ions and some don't.

Strong and weak is different to concentrated and dilute. Concentrated means a lot of substance in only a little solvent; dilute means lots of solvent and only a little substance.

Ethanoic acid is only ever a weak acid (because that is how ethanoic acid molecules are) but you can have it in a dilute form (like vinegar) or in the very smelly concentrated form.

Be careful the next time someone asks you if you want coffee strong or weak. You can tell them that you cannot change how strong it is but you might want to make it more dilute or more concentrated.