$$1.0 \times 10$$^{-3}$$\ \mathrm{M}$$

Question 1

Which of the following statements best explains why hydrochloric acid (HCl) is classified as a strong acid?

Accepted Answer

HCl completely ionizes in water, so $$[\mathrm{H_3O^+}] = [\mathrm{HCl}] in $$solution.

Question 2

A solution is prepared by dissolving 0.10 M NaOH in water. What is the pH of the solution at 25°C?

Accepted Answer

$$\mathrm{pH} = 13.00$$

Question 3

Which of the following is the correct expression for the acid ionization constant ($$K_a) $$for acetic acid ($$\mathrm{HC_2H_3O_2}$$)?

Accepted Answer

$$K_a = \frac{[\mathrm{H_3O^+}][\mathrm{C_2H_3O_2^-}]}{[\mathrm{HC_2H_3O_2}]}$$

Question 4

Which of the following household substances is most likely to have a pH greater than 10?

Accepted Answer

Household ammonia

Question 5

What is the conjugate base of $$\mathrm{H_2CO_3} ($$carbonic acid)?

Accepted Answer

$$\mathrm{$$HCO_3$$^-}$$

Question 6

A 0.10 M solution of HF (hydrofluoric acid) has a much lower $$[\mathrm{H_3O^+}]$$ than a 0.10 M solution of HCl. Why?

Accepted Answer

HF is a weak acid and only partially ionizes in water.

Question 7

Which of the following best describes an amphoteric substance?

Accepted Answer

A substance that can act as either an acid or a base depending on the reaction.

Question 8

Calculate the pOH of a solution with $$[\mathrm{OH^-}] = 2.0 	imes 10$$^{-4}$$\ \mathrm{M} at 25$$°C.

Accepted Answer

$$\mathrm{pOH} = 3.70$$

Question 9

Which of the following is a Lewis acid in the reaction $$\mathrm{BF_3$} + :\mathrm{NH_3$} \rightarrow \mathrm{F_3B-NH_3$}$$?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 10

A solution has a pH of 3.0. What is the $$[\mathrm{H_3O^+}] in $$this solution?

Accepted Answer

$$1.0 	imes 10$$^{-3}$$\ \mathrm{M}$$

Question 11

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

Accepted Answer

Sodium acetate ($$\mathrm{NaC_2H_3O_2})$$

Question 12

Which of the following best explains why $$\mathrm{Al$$^{3+}$$}$$ ions in water act as weak acids?

Accepted Answer

They are small, highly charged metal cations that polarize water molecules, leading to $$\mathrm{H_3O^+}$$ formation.

Question 13

Which of the following equations correctly represents the autoionization of water?

Accepted Answer

$$2\ \mathrm{H_2O} \rightleftharpoons \mathrm{H_3O^+} + \mathrm{OH^-}$$

Question 14

If the $$K_a$$ for acetic acid is $$1.8 	imes 10$$^{-5}$$, what is the pK_a$?

Accepted Answer

$$4.74$$

Question 15

Which of the following best describes the relationship between $$K_a$$ and acid strength?

Accepted Answer

A larger $$K_a$$ value indicates a stronger acid.

Question 16

A 0.10 M solution of a weak base has a $$K_b of$$ $$1.8 	imes 10$$^{-5}$$. Which of the following is the correct expression for K_b$?

Accepted Answer

$$K_b = \frac{[\mathrm{OH^-}][\mathrm{BH^+}]}{[\mathrm{B}]}$$

Question 17

Which of the following is a correct statement about polyprotic acids?

Accepted Answer

Each ionizable hydrogen has its own $$K_a$$, and $$K_{a1} \u003e K_{a2} \u003e K_{a3}.$$

Question 18

Which of the following best describes the pH of a 1.0 M solution of a strong acid?

Accepted Answer

The pH is close to 0.

Question 19

Which of the following is the correct formula for calculating percent ionization of a weak acid?

Accepted Answer

$$	ext{Percent Ionization} = \frac{	ext{molarity of ionized acid}}{	ext{initial molarity of acid}} 	imes 100\%$$

Acids and Bases: Properties, Definitions, and Calculations

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