Buffer solutions are used to keep pH levels constant in a number of chemical reactions. This is essential for most forms of life that survive only in a relatively small pH range. Blood is an example of buffer solution.
A buffer solution is an aqueous solution made up of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. The solution resists changes in pH when a small amount of an acid or alkali is added to it. A buffer solution changes slightly when a small quantity of a strong acid or base is added to it.
Acidic buffer solutions are made from a weak acid and one of its salts and have a pH of less than 7. An example of acidic buffer is a mixture of ethanoic acid and sodium ethanoate. With equal molar concentrations of both salt and acid, the pH of the mixture would be 4.76. The pH of the buffer solution can be changed by altering the ratio of acid to salt or by using a different acid and one of its salts. A buffer solution can also consist of more than one weak acid and its conjugate base.
Buffer solutions are critical in keeping the correct pH for enzymes. Most of the enzymes in many organisms work only under very specific conditions. Deviations of pH that are too far from the margin slow or stop the enzymes from working.