Buffers

Question 1

What is a buffer solution?

Answer 1

A buffer solution is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid that resists changes in pH upon the addition of small amounts of acid or base.

Question 2

How do you prepare a buffer solution?

Answer 2

A buffer solution can be prepared by mixing a weak acid with its salt (e.g., acetic acid and sodium acetate) or a weak base with its salt (e.g., ammonia and ammonium chloride).

Question 3

Explain how a buffer solution maintains pH when an acid is added.

Answer 3

When an acid is added to a buffer, the conjugate base present in the buffer reacts with the added H+ ions to form the weak acid, minimising the change in pH.

Question 4

Explain how a buffer solution maintains pH when a base is added.

Answer 4

When a base is added to a buffer, the weak acid present in the buffer donates H+ ions to neutralise the added OH- ions, minimising the change in pH.