A buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. It has the property of keeping its pH relatively constant when a small or moderate amount of strong acid or base is added to it. Hence, it is often used to prevent changes in the pH of a solution.

Buffer solutions are able to resist pH change due to the presence of an equilibrium between the weak acid (denoted by HA) and its conjugate base (denoted by A-), or vice versa. They can be classified into acidic buffer (weak acid and its conjugate base) or alkaline buffer (weak base and its conjugate acid).

More on the buffer solution will be discussed in the Chemical Concept tab.

References:

Content:

http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases/Buffers

Pictures:

http://chemistrahmah.com/cara-pembuatan-larutan-buffer-1.html