Buffer/acid base titration question

[LogicX]

Lets say you titrate a weak acid, HA, with a strong base, NaOH.

Now, before the equivalence point, the pH is calculated like a buffer because HA + OH- -> A- + H2O. So you have a mixture of a an acid and its conjugate base. My question is, why doesn't this act like a neutralization reaction like a strong acid and strong base? In order to get OH- you have to dissociate NaOH, so you also have Na+ in solution. Why doesn't the Na+ react with the A- to form a salt like a strong acid and strong base would?

I'm also confused about buffers in general. You have an acid and its conjugate base... why don't they react? How can they coexist in solution?

Help, I seem to have a fundamental misunderstanding of acid-base chemistry!

EDIT:

WOW I'm dumb. I've been stressing over this for hours, thinking I didn't understand chemistry anymore. But obviously, the A- is in solution so its not going to form a precipitate because salts dissociate in water. Na+ is just a spectator ion.

Still not totally sure on the second question though.

Well, actually I guess they couldn't really react and change pH. If HA reacts with A- it would just form another A-...

 

[Borek]

You are right on both counts. There is a dissolved salt in the solution in both cases, and when weak acid reacts with its conjugate base products are weak acid and conjugate base - so nothing changes.