AP Chemistry: Acids & Bases 2 — Questions and Answers
Question 1: What is the pH of a 0.001 M solution of HCl at 25 °C?
- 3 (Correct answer)
- 11
- 1
- 0.001
Correct answer: 3
HCl is a strong acid, so [H+] = 0.001 M and pH = -log(0.001) = 3.
Question 2: According to the Brønsted-Lowry theory, a base is defined as a substance that:
- Donates a proton
- Accepts a proton (Correct answer)
- Donates an electron pair
- Produces OH- ions only
Correct answer: Accepts a proton
A Brønsted-Lowry base is a proton (H+) acceptor.
Question 3: What is the conjugate base of the bicarbonate ion (HCO3-)?
- H2CO3
- CO3^2- (Correct answer)
- CO2
- OH-
Correct answer: CO3^2-
Removing a proton from HCO3- yields the carbonate ion CO3^2-.
Question 4: Which of the following is a diprotic acid?
- HCl
- HNO3
- H2SO4 (Correct answer)
- CH3COOH
Correct answer: H2SO4
Sulfuric acid (H2SO4) can donate two protons, making it diprotic.
Question 5: At 25 °C, the ion product of water Kw equals:
- 1.0 Ă— 10^-7
- 1.0 Ă— 10^-14 (Correct answer)
- 1.0 Ă— 10^14
- 7.0
Correct answer: 1.0 Ă— 10^-14
Kw = [H+][OH-] = 1.0 × 10^-14 at 25 °C.
Question 6: A solution with pOH = 4 has a pH of:
- 4
- 10 (Correct answer)
- 14
- 7
Correct answer: 10
Since pH + pOH = 14, pH = 14 - 4 = 10.
Question 7: Which substance acts as an amphoteric species, able to behave as both an acid and a base?
- HCl
- NaOH
- H2O (Correct answer)
- NaCl
Correct answer: H2O
Water can donate a proton (acid) or accept one (base), making it amphoteric.
AP Chemistry: Acids & Bases 2
What is the pH of a 0.001 M solution of HCl at 25 °C?