Buffer action

Question 1

What is a buffer?

Answer 1

A solution that resists changes in pH when small amounts of acid or alkali are added

Question 2

What is the pH of an acidic buffer?

Answer 2

Less than 7

Question 3

What does an acidic buffer contain?

Answer 3

A mixture of weak acid and its salts

Question 4

How does an acidic buffer resist changes with an acid?

Answer 4

• you need a large amount of salt
• If you add a small amount of acid, the H+ concentration increases and most of extra H+ will combine with salt to form acid
• Equilibrium shifts to the left, reducing the H+ concentration back to the original value

Question 5

How does an acidic buffer resist changes with a base?

Answer 5

• A large amount of a base is added and OH- concentration increases
• Extra OH- ions react with H+ ions to form water, removing the H+ from the solution
• More CH3CH2COOH dissociates so H+ increases until it is back to normal concentration

Question 6

What is the pH of a basic buffer?

Answer 6

pH greater than 7

Question 7

What does a basic buffer contain?

Answer 7

a mixture of a weak base and one of its salts