Question

1) Which one of the following is a Bronsted-Lowry acid?

A) (CH3)3NH+ B) CH3COOH C) HNO2 D) all of the above

2) Which one of the following statements regarding Kw is false? A) pKw is 14.00 at 25 °C.

B) The value of Kw is always 1.0 × 10-14.

C) Kw changes with temperature.

D) The value of Kw shows that water is a weak acid.

3) The Ka of benzoic acid is 6.30 × 10-5. The pH of a buffer prepared by combining 50.0 mL of a 1.00 M potassium benzoate and 50.0 mL of 1.00 M benzoic acid is ________.

A) 1.705 B) 0.851 C) 3.406 D) 4.201

4) In the reaction H2CO3 + H2O ↔ HCO3– + H3O+, the Brønsted acids are A) H2CO3 and H2O. D) H3O+ and H2CO3.

B) HCO3– and H2CO3.

C) H2O and H3O+.

5) Of the following acids, ________ is a strong acid.

A) HNO2 B) H2CO3 C) HNO3 D) HClO

6) Calculate the hydrogen ion concentration in a solution of iced tea with lemon having a pH of

2.87.

A) 2.9 x 10–2 M

C) 1.3 x 10–3 M

7) Which one of the following is the weakest acid? A) HF (Ka = 6.8 × 10-4)

B) HClO (Ka = 3.0 × 10-8)

C) HNO2 (Ka = 4.5 × 10-4)

D) HCN (Ka = 4.9 × 10-10)

B) 5.7 x 10–2 M D) 2.9 x 10–3 M

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8) The Ka of hypochlorous acid (HClO) is 3.0 × 10-8 at . What is the percent ionization of hypochlorous acid in a aqueous solution of HClO at

A) 4.5 × 10-8 B) 14 C) 2.1 × 10-5 D) 0.14

9) What is the H+ ion concentration in a 4.8 x 10–2 M KOH solution? A) 4.8 x 10–2 M

B) 1.0x 10–7 M C) 2.1 x10–13 M D) 4.8 x 10–11 M

10) HA is a weak acid. Which equilibrium corresponds to the equilibrium constant Kb for A-? A) HA (aq) + H2O (l) H2A+ (aq) + OH-(aq)

B) A- (aq) + H3O+ (aq)

C) HA (aq) + OH- (aq) H2O (l) + H+ (aq)

HA (aq) + H2O (l)

D) A- (aq) + H2O (l)

11) Using the data in the table, which of the conjugate bases below is the weakest base?

A) OAc- B) CHO2- C) ClO- D) F-

HA (aq) + OH- (aq)

12) Calculate the percent ionization of formic acid ( formic acid. The of formic acid is 1.77 ×

A) 2.74 × B) 0.0180

13) The conjugate base of CH3NH3+ is ________. A) CH3NH2+ B) CH3NH2-

H) in a solution that is 0.152 M in .

14) What is the pH of a 0.030 M aqueous solution of calcium hydroxide? A) 1.52 B) 12.48 C) 10.41

15) Which one of the following pairs cannot be mixed together to form a buffer solution? A) HONH2, HONH3Cl B) NaCl, HCl C) RbOH, HF D) KOH, HNO2

C) 3.44

C) CH3NH+

D) 0.581

D) CH3NH2

D) 12.78

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16) A solution is prepared by dissolving 0.23 mol of hypochlorous acid and 0.27 mol of sodium hypochlorite in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of HCl to this buffer solution causes the pH to drop slightly. The pH does not decrease drastically because the HCl reacts with the ________ present in the buffer solution. The of

hypochlorous acid is 1.36 × 10-3. A) O

B)

C) hypochlorite ion D) hypochlorous acid

17) An aqueous solution contains 0.500 M NaOH at 25.0 °C. The pH of the solution is ________.

A) 0.500 B) 13.70 C) 0.301 D) 7.00

18) The pH of a 0.25 M aqueous solution of hydrofluoric acid, HF, at 25.0 °C is 2.03. What is the value of Ka for HF?

A) 2.0 × 10-9 B) 1.1 × 10-9 C) 6.0 × 10-5 D) 3.5 × 10-4

19) A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained. The unknown compound is ________.

A) a strong acid B) a strong base C) a weak acid D) a weak base

20) The pH of a 0.25 M aqueous solution ammonia, NH3, at 25.0 °C is 9.50. What is the value of Kb for NH3?

A) 2.5 × 10-1 B) 4.0 × 10-19 C) 4.0 × 10-9 D) 3.2 × 10-5

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21) A buffer solution contains 0.100 M fluoride ions and 0.126 M hydrogen fluoride. What is the concentration (M) of hydrogen fluoride after addition of 9.00 mL of 0.0100 M HCl to 25.0 mL of this solution?

A) 0.0900 B) 0.122 C) 0.130 D) 0.0953

22) Calculate the hydrogen ion concentration in a solution of iced tea with lemon having a pH of 2.87.

A) 2.9x10–2M D) 2.9x10–3M B) 5.7 x 10–2 M E) 5.7 x 10–4 M C) 1.3 x 10–3 M

23) You have 500.0 mL of a buffer solution containing 0.30 M acetic acid (CH3COOH) and 0.20 M sodium acetate (CH3COONa). What will the pH of this solution be after the addition of 20.0 mL of 1.00 M NaOH solution? [Ka = 1.8 x 10–5]

A) 4.65 B) 4.71 C) 4.56 D) 4.84

Answer 1