pH Buffer Calculations

Buffer is defined as

• ability to resist pH change

• ability to resist a pH increase

• ability to prevent pH from decreasing

• ability to resist pH change when small amount of acid added

Acidic buffer is made up of

• weak acid and weak base

• weak acid and its conjugate base

• weak acid and its conjugate salt

• strong acid and its conjugate base

Which solution A and B of equal volume and concentration mixed together to form a buffer?

• Nitric acid and potassium hydroxide

• Propanoic acid and potassium hydroxide

• Nitric acid and potassium nitrate

• Propanoic acid and potassium propanoat

Which combination will form a buffer solution?

• 100.0 ml of 0.1 M HCI with 50.0 ml of 0.1 M NaOH

• 50.0 ml of 0.1 M HCI with 100.0 ml of 0.1 M NaOH

• 100.0 ml of 0.1 M CH₃COOH with 50.0 ml of 0.1 M NaOH

• 50.0 ml of 0.1 M CH₃COOH with 100.0 ml of 0.1 M NaOH

When making a buffer of pH = 5, acids with the following Ka values are available. Which would be the best acid to use?

• 1.8 x 10^-5

• 4.9 x 10^-10

• 1.8 x 10^-8

• 3.0 x 10^-8

What is a buffer?

• A solution that contains equal amounts of a weak acid and its conjugate base, or a weak base and its conjugate acid.

• A solution that contains an acid

• A solution that contains a base

• A solution that contains equal amounts of a strong acid and its conjugate base, or a strong base and its conjugate acid

What does a buffer do?

• It keeps the pH of a solution from changing very much

• It maintains the amount of acid in a solution

• It maintains the amount of base in a solution

• It keeps the pH of a solution from changing at all

How do you calculate the pH of a buffered solution?

• By determining Ka, then solving for the H⁺ concentration to determine the pH

• By determining the OH^- concentration.

• By using the equation Ka = [H₃O^+][X^-]

• By using the equation Ka = [HX⁺][X^-] / [H₃O⁺]

Which of the following is an example of a natural buffer?

• Blood

• Freshwater

• Acetic acid (CH₃COOH)

• Ammonium (NH₃)

Which two types of chemicals are necessary buffer ingredients?

• A strong acid and a strong base

• A weak acid or weak base and the salt of the weak acid or weak base

• A weak acid and weak base

• Water and a salt