Practice Test

1. Which of the following does NOT represent an acid followed by its conjugate base?

• a) H₃O+ / H₂O

• b) HCN / CN-

• c) HCl / Cl-

• d) HC₂H₃O₂ / OH-

• e) All are acids followed by their conjugate base

2. According to the Bronsted-Lowry definition, a base is

• a) a substance that increases the hydroxide ion concentration of a solution

• b) a substance that can accept a proton from an acid

• c) a substance that can donate an electron pair to the formation of a covalent bond

• d) a substance that increases the anion formed by the autoionization of the solvent

• e) a substance that donates a proton

3. The equilibrium constant for the reaction

A- + H+ <----> HA   is called:

• a) Ka

• b) Kb

• c) 1/Ka

• d) Kw/Kb

• e) KwKa

Answer explanation

The equilibrium constant for the reaction A- + H+ <----> HA is represented as Ka. Therefore, the reverse reaction, HA <----> A- + H+, has a constant of 1/Ka, making option c) 1/Ka the correct answer.

4. At 0 degrees Celsius, the Kw for water is 1.2 x 10^-15.  The pH of pure water at this temperature is

• a) 7.00

• b) 6.88

• c) 7.56

• d) 7.46

• e) none of these

5. Given   HCN(aq) + HCO₃-(aq) <-----> CN-(aq) + H₂CO₃(aq)

If K< 1, what is the strongest base in this system?

• a) HCN

• b) HCO₃-

• c) CN-

• d) H₂CO₃

• e) H₂O

6. The following acids are listed in order of decreasing acid strength in water. 

HI > HNO₂ > CH₃COOH > HClO > HCN

According to Bronsted-Lowry theory, which of the following ions is the weakest base?

• a) I^-

• b) NO₂^-

• c) CH₃COO^-

• d) ClO^-

• e) CN^-

7. Which of the following is an acid?

• a) HCOOH

• b) CH₃OH

• c) KOH

• d) NH₃

• e) CH₃NH₂

8. What is the strongest acid?

• a) HClO₂

• b) HClO₃

• c) HClO₄

• d) HF

• e) HOCl

Answer explanation

HClO4, or perchloric acid, is the strongest acid among the options listed. It completely dissociates in solution, making it a strong acid, while HClO2, HClO3, HF, and HOCl are weaker acids.

9. Which of the following reactions does not proceed significantly to the right in aqueous solution?

• a) HCl + H₂O ----> H₃O+ + Cl^-

• b) H₃O+ + OH- ----> 2H₂O

• c) H₂O + HSO₄- ----> H₂SO₄ + OH^-

• d) HCN + OH- ----> H₂O + CN^-

10. What is the [H⁺] in a solution which shows a pH of 2.30?

• a) 2.3M

• b) 11.7M

• c) 5.0 x 10^-3M

• d) 2.0 x 10^-12M

• e) none of these