【How-to】How to make a buffer

Buffers do so by being composed of certain pairs of solutes: either a weak acid plus a salt derived from that weak acid or a weak base plus a salt of that weak base. For example, a buffer can be composed of dissolved acetic acid (HC ₂H ₃O ₂, a weak acid) and sodium acetate (NaC ₂H ₃O ₂, a salt derived from that acid).