Martin et al (1989) defined buffer as a solution that has the ability to resist change in pH, when small amounts of strong acids or bases are added to it. For example, when 0.01 mole of strong acids or base is added to distilled water, the pH drops to 2 with the acids and rises to 12 with the base. If the same amount of acid or base is added to an acetic acid-sodium acetate buffer, the pH may only change a fraction of a unit.
Buffers are important in many areas of chemistry. When the pH must be controlled during the course of a reaction, the solutions are often buffered. This is often the case in biochemistry when enzymes or proteins are being studied. Our blood is often buffered to a pH of 7.4. Variations of a few tenths of a pH unit can cause illness or death. Acidosis is the condition when pH drops too low. Alkalosis is the condition when pH becomes higher than normal. Acidosis or alkalosis affects the functions of the heart.
In buffer solution two species are required one is capable of reaction with OH- and the other will react with H3O+. The two species must not react with each other. Many buffers are prepared by combing a weak acid and its conjugate (acetic acid and sodium acetate) or a weak base and its conjugate (ammonia and ammonium chloride). In general, the pH range in which a buffer solution is effective is + or – one pH unit on either side of the pka.
Buffering however is the tendency of a solution to resist change in pH following addition of acid or base, according to Martin et al, 1989.
1.1 CONSTITUENT OF A BUFFER
A buffer is a solution made up of a weak acid and its conjugate base, similarly a buffer solution may be made up of a weak and its conjugate acid.
1. CH3COOH (acetic acid) CH3COO-
2. CH3NH CH3NH2
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