Question

define a buffer and give two examples of buffer solutions?

Answer 1

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable. This is important for processes and/or reactions which require specific and stable pH ranges. To effectively maintain a pH range, a buffer must consist of a weak conjugate acid-base pair, meaning either a. a weak acid and its conjugate base, or b. a weak base and its conjugate acid.

1.Acidic buffer solution contains equimolar quantities of a weak acid and its salt with strong base. For example: an acetic acid, CH₃COOH and sodium acetate I.e. CH₃COONa. A solution containing equimolar quantities of acetic acid and sodium acetate maintains its pH value around 4.74.

2. Basic buffer solution contains equimolar quantities of a weak base and its salt with strong acid. For example: ammonium hydroxide i.e. NH₄OH and ammonium chloride I.e. NH₄Cl. A solution containing equimolar quantities of ammonium hydroxide and ammonium chloride maintains its pH value around 9.25.