Question

How do you calculate the pH of a buffer solution?

Answer 1

By use of the buffer equation:

`pH = pK_a + log_10([[A^-]]/[[HA]]).`

Explanation:

I am not going to derive this equation here (it is rather simple to do and worth doing), but it tells us that the `pH` of a given buffer should remain tolerably close to the `pK_a` of the acid that comprises the buffer. Added base or acid simply protonates/deprotonates the given base/acid, and should not grossly change solution `pH`.