What are the few requirements of buffer systems? Well, first, we have to have a weak acid and a weak base. And second, the weak acid cannot react with our weak base, because if they did, our buffer system would be neutralized and we wouldn't have a buffer to work with. Now, what's one thing that satisfies these two requirements? Well, that's a conjugate acid base pair. Whenever a conjugate acid reacts with a conjugate base, it produces another conjugate acid and base pair for example, acetate ion and acetic acid react to produce acetate ion and acetic acid.