Q: What is the $pH$ of a solution with a hydronium ion concentration of $2.5 \times 10^{-4}$ M?

$pH = -\log(2.5 \times 10^{-4}) \approx 3.60$

Q: A solution has $[OH^-] = 1.0 \times 10^{-9}$ M. What is the $[H_3O^+]$ in this solution at $25^\circ$C?

$[H_3O^+] = \dfrac{1.0 \times 10^{-14}}{1.0 \times 10^{-9}} = 1.0 \times 10^{-5}$ M

Q: What is the $pH$ of seawater with $[H_3O^+] = 3.67 \times 10^{-9}$ M?

$pH = -\log(3.67 \times 10^{-9}) \approx 8.44$ (basic)

Question 1

Which of the following best describes a Bronsted-Lowry acid?

Accepted Answer

A compound that donates a hydrogen ion ($H^+$) in solution.

Question 2

What is the $pH$ of a solution with a hydronium ion concentration of $2.5 	imes 10^{-4}$ M?

Accepted Answer

$pH = -\log(2.5 	imes 10^{-4}) \approx 3.60$

Question 3

A solution has $[OH^-] = 1.0 	imes 10^{-9}$ M. What is the $[H_3O^+]$ in this solution at $25^\circ$C?

Accepted Answer

$[H_3O^+] = \dfrac{1.0 	imes 10^{-14}}{1.0 	imes 10^{-9}} = 1.0 	imes 10^{-5}$ M

Question 4

Which of the following is a strong acid?

Accepted Answer

HNO_3 (nitric acid)

Question 5

Which statement about the dissociation of water is correct?

Accepted Answer

Water dissociates to produce equal concentrations of $H_3O^+$ and $OH^-$ ions.

Question 6

A buffer solution is made by mixing acetic acid ($HC_2H_3O_2$) and sodium acetate ($NaC_2H_3O_2$). What happens when a small amount of $HCl$ is added?

Accepted Answer

The acetate ion reacts with the added $H^+$ to form more acetic acid, minimizing the pH change.

Question 7

Which of the following reactions is a neutralization reaction?

Accepted Answer

$HCl(aq) + NaOH(aq) \rightarrow H_2O(l) + NaCl(aq)$

Question 8

Which of the following pairs are conjugate acid-base pairs?

Accepted Answer

$NH_4^+$ and NH_3$

Question 9

If the concentration of $H_3O^+$ in a solution is $1.0 	imes 10^{-10}$ M and the concentration of $OH^-$ is $7.2 	imes 10^{-5}$ M, is the solution acidic, basic, or neutral?

Accepted Answer

Basic, because $[OH^-] > [H_3O^+]$

Question 10

Which of the following is true about weak acids?

Accepted Answer

They partially dissociate in water and exist in equilibrium with their conjugate base.

Question 11

A patient with emphysema cannot efficiently remove $CO_2$ from their blood. According to Le Chatelier’s Principle, what happens to the blood pH?

Accepted Answer

Blood pH decreases (becomes more acidic) as equilibrium shifts right to produce more $H_2CO_3$.

Question 12

Which of the following is NOT a buffer system?

Accepted Answer

$NaOH$ and $NaCl$

Question 13

What is the $pH$ of seawater with $[H_3O^+] = 3.67 	imes 10^{-9}$ M?

Accepted Answer

$pH = -\log(3.67 	imes 10^{-9}) \approx 8.44$ (basic)

Question 14

Which of the following is a polyprotic acid?

Accepted Answer

$H_2SO_4$

Question 15

What happens to the equilibrium of the reaction $CH_3CH(OH)COOH + HCO_3^- \rightleftharpoons CH_3CH(OH)COO^- + H_2CO_3$ if more lactic acid ($CH_3CH(OH)COOH$) is added?

Accepted Answer

The equilibrium shifts to the right to use up the added lactic acid.

Question 16

Which of the following is the correct balanced equation for the complete neutralization of sulfuric acid ($H_2SO_4$) with sodium hydroxide ($NaOH$)?

Accepted Answer

$H_2SO_4(aq) + 2NaOH(aq) \rightarrow 2H_2O(l) + Na_2SO_4(aq)$

Question 17

Beer has a $pH$ of 5.0. Is beer acidic, basic, or neutral?

Accepted Answer

Acidic, because $pH < 7$

Question 18

Which of the following is true about the equilibrium of a weak acid in water?

Accepted Answer

At equilibrium, both reactants and products are present, but the weak acid is in the highest concentration.

Chapter 10: Acids, Bases, and Equilibrium – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards