8.7 Buffer Solution

Do you know that our blood maintains a constant pH, irrespective of a number of cellular acid – base reactions. Is it possible to maintain a constant hydronium ion concentration in such reactions? Yes, it is possible due to buffer action. Buffer is a solution which consists of a mixture of a weak acid and its conjugate base (or) a weak base and its conjugate acid.

This buffer solution resists drastic changes in its pH upon addition of a small quantities of acids (or) bases, and this ability is called buffer action. The buffer containing carbonic acid (H CO ) and its conjugate base HCO - is present in our blood. There are two types of buffer solutions. .

Acidic buffer solution : a solution containing a weak acid and its salt. Example : solution containing acetic acid and sodium acetate . Basic buffer solution : a solution containing a weak base and its salt. Example : Solution containing NH OH