MODULE 5: Buffers and Neutralisation

Question 1

Buffer definition:

Answer 1

A solution that minimises the pH change when small amounts of acid or alkali are added

Question 2

Components of a buffer solution:

Answer 2

Weak acid and its conjugate acid-base pairing, in order to remove any added OH- or H+ (equilibrium)

Question 3

Action on a buffer solution when acid is added:

Answer 3

• H+ increases
• Excess H+ reacts with A- (conjugate base pair)
• Equilibrium shifts back to the left, so most of the added H+ ions get used

Question 4

Action on a buffer solution when alkali is added:q

Answer 4

• OH- increases
• Small volume of H+ reacts to form water (H2O)
• Equilibrium shifts to the right to restore the volume of H+ ions