Question 1

Which of the following statements best describes a Brønsted-Lowry acid?

Accepted Answer

A substance that donates a proton (H+) to another molecule or ion.

Question 2

Which of the following is the conjugate base of HSO4–?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 3

A solution has $$[\mathrm{H_3O^+}] = 2.0 	imes 10$$^{-5}$$\ \mathrm{M}. $$What is its pH?

Accepted Answer

$$4.70$$

Question 4

Which of the following acids is triprotic?

Accepted Answer

Phosphoric acid ($$\mathrm{H_3PO_4})$$

Question 5

Which of the following best explains why the Ka value for the second dissociation of a polyprotic acid is much lower than the first?

Accepted Answer

It is more difficult to remove a positively charged H+ from a negatively charged anion.

Question 6

A buffer solution is prepared using acetic acid ($$\mathrm{CH_3COOH}$$, $$pK_a = 4.74) $$and sodium acetate. What is the pH of the buffer if $$[\mathrm{CH_3COOH}] = 0.10\ \mathrm{M}$$ and $$[\mathrm{CH_3COO^-}] = 0.20\ \mathrm{M}$$?

Accepted Answer

$$5.04$$

Question 7

Which of the following salts will produce a basic solution when dissolved in water?

Accepted Answer

NaCN

Question 8

What is the normality (N) of a $$0.50\ \mathrm{M}$$ solution of $$\mathrm{H_2SO_4}$$?

Accepted Answer

$$1.0\ \mathrm{N}$$

Question 9

A cleaning solution has $$[\mathrm{OH^-}] = 1.0 	imes 10$$^{-3}$$\ \mathrm{M}. $$What is the pH of the solution?

Accepted Answer

$$11.0$$

Question 10

Which of the following equations correctly represents the neutralization reaction between hydrochloric acid and potassium hydroxide?

Accepted Answer

$$\mathrm{HCl(aq) + KOH(aq) \rightarrow H_2O(l) + KCl(aq)}$$

Question 11

Which of the following best describes the role of water in the reaction $$\mathrm{NH_3$ + H_2O \rightleftharpoons NH_4$^+ + OH^-}$$?

Accepted Answer

Water acts as a Brønsted-Lowry acid.

Question 12

A 5.00 mL sample of vinegar is titrated with 44.5 mL of $$0.100\ \mathrm{M}$$ NaOH. What is the molarity of acetic acid in the vinegar?

Accepted Answer

$$0.890\ \mathrm{M}$$

Question 13

Which of the following is true about buffer solutions?

Accepted Answer

They contain a weak acid and its conjugate base.

Question 14

Which of the following is the correct expression for the acid dissociation constant ($$K_a) $$for the reaction $$\mathrm{HA(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + A^-(aq)}$$?

Accepted Answer

$$K_a = \dfrac{[\mathrm{H_3O^+}][\mathrm{A^-}]}{[\mathrm{HA}]}$$

Question 15

Which of the following best explains why antacids containing carbonates are effective in neutralizing stomach acid?

Accepted Answer

Carbonates react with acid to produce water and carbon dioxide gas.

Question 16

Which of the following is the correct Henderson-Hasselbalch equation for a buffer solution?

Accepted Answer

$$\mathrm{pH = pK_a + \log \left( \dfrac{[A^-]}{[HA]} \right)}$$

Question 17

A buffer solution contains $$0.100\ \mathrm{M} HF $$and $$0.120\ \mathrm{M}$$ NaF. The $$K_a of HF is$$ $$3.5 	imes 10$$^{-5}$$. What is the pH of the buffer?

Accepted Answer

$$3.54$$

Question 18

Which of the following best describes the direction of an acid-base equilibrium?

Accepted Answer

It always favors the formation of the weaker acid and base.

Acids and Bases: Definitions, Strength, Equilibria, and Applications

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