ACIDS
AND BASES
(Quiz 5-2)

1. The pK_a of acetic acid, CH₃COOH, is 4.76.  What is the value of the equilibrium constant K_eq, for the following equilibrium? [The concentration of water in a dilute aqueous solution is 55 M]?

(A) 3.2 x 10⁷

(B) 3.15

(C) 3.2  x 10^-7

(D) --3.2  x 10⁷

2. Which of the following compounds is the strongest acid?

(A) CH₃COOH

(B) ClCH₂COOH

(C) CH₃CH₂OH

(D) ClCH₂CH₂OH

3. Which of the following anions is the strongest base?

(A) CH₃COO^-

(B) HO^-

(C) NH₂^-

(D) Cl^-

4. Which of the following compounds is the strongest acid?

(A) CH₃OCH₃

(B) CH₃CH₂OH

(C) CH₃CHO

(D) CH₃CO₂H

5. Which of the following is present in the highest concentration upon dissolution of H₂SO₄ in water?

(A) H₂SO₄

(B) H⁺

(C) H₃O⁺

(D) HO^-

6. Which of the following terms describes the role of ethanol in the acid-base reaction shown?

(A) Brønsted-Lowry acid

(B) Brønsted-Lowry base

(C) Lewis base

(D) none of the above

7. Which of the following terms describes the role of ethyne in the acid-base reaction shown?

(A) Brønsted-Lowry acid

(B) Brønsted-Lowry base

(C) Lewis base

(D) none of the above

8. Which species is the conjugate acid in the following acid-base reaction?

(A) 1

(B) 2

(C) 3

(D) 4

9. What is the value of the equilibrium constant, K_eq, for the following reaction?

(A) 10¹³

(B) 10^-13

(C) 13

(D) ¹/₁₃

10. Which of the following concepts can be used to rationalize the observation that acetic acid is a stronger acid than methanol?

(A) electronegativity

(B) resonance

(C) valence shell electron pair repulsion theory

(D) Pauli exclusion principle