Buffer Solutions for Grade 12

What is meant by a buffer solution?

• A buffer solution is a type of solvent used for dissolving solids.

• A buffer solution is a mixture that only contains water and salt.

• A buffer solution is a solution that resists changes in pH upon the addition of small amounts of acid or base.

• A buffer solution is a solution that changes pH dramatically when acid or base is added.

The main components of an acidic buffer solution are:

• A strong acid and its conjugate base.

• A weak base and its conjugate acid.

• A strong base and a salt.

• A weak acid and its conjugate base.

If the pH of a buffer solution is 4, the concentration of weak acid (HA) and conjugate base (A-) can be expressed by the formula:

• [HA] = [A-] at pH 4 if pKa is also 4.

• [HA] = [A-] at pH 4 if pKa is 7.

• [HA] = 2[A-] at pH 4 if pKa is 4.

• [HA] > [A-] at pH 4 if pKa is 4.

Which of the following is a characteristic of buffer solutions?

• They change pH rapidly.

• They resist changes in pH.

• They are only effective in strong acids.

• They can only be used in laboratory settings.

What happens to the pH of a buffer solution when a small amount of strong acid is added?

• The pH of the buffer solution increases significantly.

• The pH of the buffer solution remains unchanged.

• The pH of the buffer solution becomes neutral.

• The pH of the buffer solution decreases slightly.

What is the role of the conjugate base in a buffer solution?

• The conjugate base has no effect on pH levels.

• The conjugate base helps maintain pH stability by neutralizing added acids.

• The conjugate base increases the acidity of the solution.

• The conjugate base reacts with bases to form acids.

Which of the following pairs can form a buffer solution?

• Sodium hydroxide and potassium sulfate

• Acetic acid and sodium acetate

• Ammonia and ammonium nitrate

• Hydrochloric acid and sodium chloride

How does the Henderson-Hasselbalch equation relate to buffer solutions?

• It relates the pH of a solution to the volume of solvent used in a reaction.

• The Henderson-Hasselbalch equation describes the relationship between pH and the ratio of the concentrations of acid and its conjugate base in a buffer solution.

• The Henderson-Hasselbalch equation calculates the solubility of salts in water.

• The equation determines the temperature at which a buffer solution is effective.

What is the effect of dilution on the pH of a buffer solution?

• The pH of a buffer solution increases significantly upon dilution.

• The pH of a buffer solution decreases dramatically upon dilution.

• Dilution has no effect on the pH of a buffer solution.

• The pH of a buffer solution remains relatively stable upon dilution.

Why are buffer solutions important in biological systems?

• They provide nutrients to cells.

• Buffer solutions are important because they stabilize pH levels in biological systems.

• They act as a source of energy for reactions.

• They increase the temperature of biological systems.