How does the buffer work?

 A buffer solution is a solution of a specific pH in which a small amount of acid and a small amount of alkali are added but the pH does not change much. There are generally two types of buffer solutions:

1) Acidic buffer.

2) Alkaline buffer.

 The weak acid solution of its conjugate base is an acidic buffer solution. And a weak base and its conjugate acid is an alkaline buffer solution.

 Such as:

CH3COOH + CH3COONa —------ (1)

NH4OH + NH4Cl —------- (2)

Here reaction (1) is an acidic buffer and reaction (2) is an alkaline buffer.

From reaction 1 we get,

CH3COOH=CH3COONa-   +H+

If we add a small amount of acid (H+) inside this solution, it will react with CH3COO to produce unsaturated CH3COOH.

CH3COONa = CH3COO- + Na+

 And if we add a small amount of alkali (OH), it will react with H+ to form H2O. And as much as OH- reacts with H+, H+ will separate from CH3COOH and keep the pH of the solution unchanged.