Please help - questions on pH's and titrations.?

1) I don't understand why the pH of water is different at different temperatures even if it is always neutral??? argh I really dont understand this. I know H2O will dissociate to give equal amounts of H+ and OH- ions but???



2) How do you tell which acids are stronger? eg I know the stronger the acid the more it dissociates but why is for example HCl a stronger base than CH3COOH?



3) Why when doing a titration does the pH change so suddenly?



I would be grateful if anyone could help me with any of these three. I have been revising for my exam and these are 3 things I came across and the text book doesn't explain too well... Thankyou :)Please help - questions on pH's and titrations.?
1) [H+]=[OH-]. The amounts of H+ and OH- ions are the same at any temprature.

2) HCl is a strong acid as it dissociates fully in solution. Ethanoic acid slightly dissociates, so is weak.

3) This is the equivalence point. It is here that all the acid or base is neutralised.