Question

What is a buffer? How do they work? How can they maintain pH?

Answer 1

Well, a buffer is a solution of a weak base, and its conjugate acid in APPRECIABLE quantities...

Explanation:

...and a buffer acts to mimimize GROSS changes in `pH`...

See this old link.

A buffer is composed of a weak base, and its conjugate acid in appreciable quantities that acts to resists gross changes in `pH`...and for such a system...

`pH=pK_a+log_10{[[A^-]]/[[HA]]}`

What is `pH` when `[HA]=[A^-]`?