1. The problem statement, all variables and given/known data What's a buffer? 2. Relevant equations The most general definition is that a buffer resists changes in pH. However, my textbook and ChemWiki by UC Davis maintain that a buffer is composed of conjugate pairs (i.e. a base and its conjugate acid). 3. The attempt at a solution Is a buffer necessarily composed of its base and its conjugate acid or acid and its conjugate base? I think no .... can't some salts be buffers? Such as ammonium sulfate?