Skip to content11. The pH scale is used to measure:
- A) Hydrogen ion concentration
- B) Temperature
- C) Pressure
- D) Solubility
- Answer: A
12. What is the pH of pure water at 25°C?
- A) 0
- B) 7
- C) 14
- D) 10
- Answer: B
13. A solution with a pH of 3 is:
- A) Neutral
- B) Basic
- C) Acidic
- D) Alkaline
- Answer: C
14. If the hydrogen ion concentration [H⁺] of a solution is 1 × 10⁻⁴ M, what is the pH?
- A) 4
- B) 10
- C) 7
- D) 1
- Answer: A
15. The relationship between pH and hydrogen ion concentration is given by the equation:
- A) pH = log[H⁺]
- B) pH = -log[H⁺]
- C) pH = [H⁺] + 14
- D) pH = 14 – [H⁺]
- Answer: B
16. Which of the following is a characteristic of a buffer solution?
- A) It changes pH drastically with small additions of acid or base
- B) It resists changes in pH upon the addition of small amounts of acid or base
- C) It has a pH of exactly 7
- D) It is always made from a strong acid and a strong base
- Answer: B
17. The Henderson-Hasselbalch equation relates pH to:
- A) Concentration of solute and solvent
- B) Concentration of hydrogen ions only
- C) Ratio of the concentration of the conjugate base to the acid
- D) Temperature and pressure
- Answer: C
18. Which of the following pairs can form a buffer solution?
- A) Strong acid and strong base
- B) Weak acid and its conjugate base
- C) Weak base and strong acid
- D) Strong acid and salt
- Answer: B
19. What is the pH of a buffer solution made from 0.1 M acetic acid and 0.1 M sodium acetate?
- A) 4.76
- B) 7.00
- C) 3.00
- D) 10.00
- Answer: A
20. What is the pH of a solution with a hydroxide ion concentration [OH⁻] of 1 × 10⁻³ M?
- A) 11
- B) 4
- C) 10
- D) 7
- Answer: A
