8.3 The pH Scale

Which of the following formulas correctly represents the relationship between pH and the concentration of hydrogen ions?

A. pH = Log[H+]

B. pH = -Log[H+]

C. pH = [H+]

D. pH = 1/Log[H+]

If the pH of a solution is 5, how would you classify this solution?

A. Strongly acidic

B. Weakly acidic

C. Neutral

D. Basic

Which of the following is true about the relationship between pH and pOH?

A. pH + pOH = 14

B. pH - pOH = 7

C. pH * pOH = 14

D. pH / pOH = 2

What does a high pKa value for an acid indicate?

A. The acid is strong.

B. The acid is weak.

C. The acid is neutral.

D. The acid is basic.

Which of the following solutions has the lowest concentration of H+ ions?

A. pH 2

B. pH 5

C. pH 7

D. pH 9

a) Define the term pH and explain its significance in determining the acidity or basicity of a solution. [2]

b) A solution has a [H+] concentration of 1 x 10^-5 mol/L. Use the given formula to calculate its pH. [2]

a) Differentiate between strong and weak acids in terms of their pH values. [2]

b) If a strong acid has a pH of 2, what would be the [H+] concentration of the solution? [2]

a) Describe the relationship between pH and pOH in a solution. [2]

b) If a solution has a pOH of 8, determine its pH. [2]

a) Explain the significance of pKa in acid-base equilibria. [3]

b) A weak acid, HA, has a pKa of 4.5. If the pH of a solution containing this acid is 4.5, what can you infer about the concentrations of HA and A-? [2]

c) How would the pH of the solution change if more of the weak acid, HA, was added? [2]

a) Describe the difference between the degree of ionisation in strong and weak acids. [3]

b) Why do strong acids have a higher degree of ionisation than weak acids? [2]

c) If a strong acid is diluted, how does its degree of ionisation change? [2]