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

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

Q: A solution is prepared by dissolving $$0.10\ \mathrm{mol} of$$ $$\mathrm{NH_3$} in $$enough water to make $$1.0\ \mathrm{L} of $$solution. Given $$K_b$$ for $$\mathrm{NH_3$} is$$ $$1.8 \times 10$$^{-5}$$, what is the $$[\mathrm{OH^-}]$$ at equilibrium? (Assume x$$ \ll 0.10$$)

$$1.3 \times 10$$^{-3}$$\ \mathrm{M}$$

Question 1

Which of the following statements best describes the difference between the Arrhenius and Brønsted-Lowry definitions of acids and bases?

Accepted Answer

Arrhenius acids produce $$\mathrm{H^+} in $$water, while Brønsted-Lowry acids donate protons to other species.

Question 2

Which of the following is the conjugate base of $$\mathrm{$$HCO_3$$^-}$$?

Accepted Answer

$$\mathrm{CO_3$^{2-}}$$

Question 3

Which of the following acids is considered a strong acid in aqueous solution?

Accepted Answer

Hydrochloric acid ($$\mathrm{HCl})$$

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

Sodium acetate ($$\mathrm{NaCH_3COO})$$

Question 6

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

Accepted Answer

$$4.74$$

Question 7

Which of the following statements about polyprotic acids is correct?

Accepted Answer

Each successive proton is harder to remove, so $$K_{a1} \u003e K_{a2} \u003e K_{a3}.$$

Question 8

Which of the following best explains why $$\mathrm{HCl} is a $$stronger acid than $$\mathrm{HF}$$?

Accepted Answer

The H–Cl bond is weaker and longer than the H–F bond, making it easier to ionize.

Question 9

A solution is prepared by dissolving $$0.10\ \mathrm{mol} of$$ $$\mathrm{NH_3$} in $$enough water to make $$1.0\ \mathrm{L} of $$solution. Given $$K_b$$ for $$\mathrm{NH_3$} is$$ $$1.8 	imes 10$$^{-5}$$, what is the $$[\mathrm{OH^-}]$$ at equilibrium? (Assume x$$ \ll 0.10$$)

Accepted Answer

$$1.3 	imes 10$$^{-3}$$\ \mathrm{M}$$

Question 10

Which of the following is a Lewis acid but not a Brønsted-Lowry acid?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 11

If $$K_w = 1.0 	imes 10$$^{-14}$$ at 25$$^\circ\mathrm{C}$$, what is the pK_w$?

Accepted Answer

$$14$$

Question 12

Which of the following best describes the relationship between $$K_a$$, $$K_b$$, and $$K_w$$ for a conjugate acid-base pair?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 13

A solution has $$[\mathrm{OH^-}] = 2.0 	imes 10$$^{-4}$$\ \mathrm{M}. $$What is the pH?

Accepted Answer

$$10.3$$

Question 14

Which of the following factors increases the strength of an oxyacid?

Accepted Answer

Increasing the electronegativity of the central atom

Question 15

Which of the following is the correct $$pOH$$ for a solution with $$[\mathrm{H_3O^+}] = 1.0 	imes 10$$^{-5}$$\ \mathrm{M}$$?

Accepted Answer

$$9$$

Question 16

Which of the following best describes the effect of resonance on acid strength?

Accepted Answer

Resonance stabilizes the conjugate base, making the acid stronger.

Question 17

Which of the following is the correct expression for the acid dissociation constant ($$K_a) $$for acetic acid ($$\mathrm{CH_3COOH}$$)?

Accepted Answer

$$K_a = \dfrac{[\mathrm{CH_3COO^-}][\mathrm{H_3O^+}]}{[\mathrm{CH_3COOH}]}$$

Question 18

A patient is suffering from heartburn due to excess stomach acid ($$\mathrm{HCl}). $$Which compound would best neutralize the acid?

Accepted Answer

Magnesium hydroxide ($$\mathrm{Mg(OH)_2})$$

Question 19

Which of the following is the correct relationship between $$pK_a$$, $$pK_b$$, and $$pK_w$$?

Accepted Answer

$$pK_a + pK_b = pK_w$$

Question 20

Which of the following is the best example of a Brønsted-Lowry base?

Accepted Answer

Ammonia ($$\mathrm{NH_3$}$$), because it accepts a proton to form $$\mathrm{NH_4$^+}$$

Chapter 17: Acids and Bases – Study Guide

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