Q: A solution has a pH of 3.0. What is the hydronium ion concentration, $$[H_3O^+]$$?

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

Q: A rainwater sample has a pH of 4.70. What is the $$[H_3O^+] in $$this sample?

$$ 2.0 \times 10^{-5} \ \mathrm{M} $$

Question 1

Which of the following best describes a Lewis acid?

Accepted Answer

A substance that accepts an electron pair.

Question 2

Which equation correctly represents the auto-ionization of water?

Accepted Answer

$$ \mathrm{H_2O(l) + H_2O(l) \rightleftharpoons H_3O^+(aq) + OH^-(aq)} $$

Question 3

A solution has a pH of 3.0. What is the hydronium ion concentration, $$[H_3O^+]$$?

Accepted Answer

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

Question 4

Which of the following is NOT a strong acid?

Accepted Answer

HC2H3O2

Question 5

What is the pH of a solution with $$[OH^-] = 2.9 	imes 10$$^{-4}$$ \ \mathrm{M} at 25$$°C?

Accepted Answer

$$ 10.46 $$

Question 6

Which of the following statements about weak acids is correct?

Accepted Answer

The smaller the $$pK_a$$, the stronger the acid.

Question 7

A 0.15 M solution of acetic acid ($$K_a = 1.8 	imes 10$$^{-5}$$) has an equilibrium $$[H_3O^+]$$ of 1.6$$ 	imes $$10^{-3} M. $$What is the percent ionization?

Accepted Answer

$$ 1.1\% $$

Question 8

Which of the following best describes an Arrhenius base?

Accepted Answer

A substance that produces OH‒ ions in water.

Question 9

If the $$K_w at 25$$°C is $$1.0 	imes 10$$^{-14}$$, what is the relationship between pH and pOH?

Accepted Answer

$$ \mathrm{pH + pOH = 14.00} $$

Question 10

Which of the following is an example of a Brønsted-Lowry acid-base reaction?

Accepted Answer

$$ \mathrm{NH_3(aq) + H_2O(l) \rightleftharpoons NH_4^+(aq) + OH^-(aq)} $$

Question 11

A rainwater sample has a pH of 4.70. What is the $$[H_3O^+] in $$this sample?

Accepted Answer

$$ 2.0 	imes 10^{-5} \ \mathrm{M} $$

Question 12

Which of the following is true about the effect of dilution on the percent ionization of a weak acid?

Accepted Answer

Dilution increases the percent ionization.

Question 13

Which of the following is the correct expression for the acid dissociation constant ($$K_a) $$for a generic weak acid $$HA$$?

Accepted Answer

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

Question 14

Which of the following best describes an amphoteric substance?

Accepted Answer

A substance that can act as either an acid or a base.

Question 15

A solution has $$[OH^-] = 1.0 	imes 10$$^{-6}$$ \ \mathrm{M}. $$What is its pOH and is the solution acidic, basic, or neutral?

Accepted Answer

pOH = 6.00, basic

Question 16

Which of the following is true about conjugate acid-base pairs?

Accepted Answer

A conjugate acid is formed when a base gains a proton.

Question 17

Which of the following is the correct relationship between $$K_a$$ and $$pK_a$$?

Accepted Answer

$$ pK_a = -\log K_a $$

Question 18

Which of the following is a real-life application of the pH scale?

Accepted Answer

Determining the acidity of rainwater to monitor acid rain.

Acids and Bases: Definitions, Properties, and Calculations

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