They completely ionize, so $[\text{H}^+]$ and $[\text{OH}^-]$ are equal to the initial concentration of the acid or base.

$[\text{H}^+] = 10^{-4.34}\ \text{M}$

$1.36 \times 10^{-5}\ \text{mol}$

$[\text{H}^+] = 7.1 \times 10^{-4}\ \text{M}$

Because the product of $[\text{H}^+]$ and $[\text{OH}^-]$ is always $1.0 \times 10^{-14}$ at 25°C.

$[\text{OH}^-] = 2 \times \dfrac{0.25}{1.2}\ \text{M}$

$\text{pOH} = -\log([\text{OH}^-])$

Question 1

Which of the following statements best describes the behavior of strong acids and strong bases in water?

Accepted Answer

They completely ionize, so $[	ext{H}^+]$ and $[	ext{OH}^-]$ are equal to the initial concentration of the acid or base.

Question 2

Given a 0.25 M solution of HCl, a strong acid, what is the concentration of $[	ext{H}^+]$ in the solution?

Accepted Answer

$0.25\ 	ext{M}$

Question 3

A 0.398 M solution of Ba(OH)$_2$ is prepared. What is the pOH of the solution? (Assume complete dissociation.)

Accepted Answer

$	ext{pOH} = -\log(0.796)$

Question 4

Which of the following ions is NOT typically found in a strong base?

Accepted Answer

$	ext{NH}_4^+$

Question 5

If the pH of a solution is 4.34, what is the $[	ext{H}^+]$ concentration?

Accepted Answer

$[	ext{H}^+] = 10^{-4.34}\ 	ext{M}$

Question 6

A 25 mL sample of 5.45 	imes 10^{-4} M LiOH is prepared. What is the number of moles of LiOH in the sample?

Accepted Answer

$1.36 	imes 10^{-5}\ 	ext{mol}$

Question 7

HI is a strong acid with $K_a = 3.2 	imes 10^9$. If you have a 7.1 	imes 10^{-4} M solution of HI, what is the $[	ext{H}^+]$ concentration?

Accepted Answer

$[	ext{H}^+] = 7.1 	imes 10^{-4}\ 	ext{M}$

Question 8

Which of the following best explains why the pH and pOH of a strong acid and strong base solution are related by $	ext{pH} + 	ext{pOH} = 14$ at 25°C?

Accepted Answer

Because the product of $[	ext{H}^+]$ and $[	ext{OH}^-]$ is always $1.0 	imes 10^{-14}$ at 25°C.

Question 9

A solution is made by dissolving 0.25 mol of Ca(OH)$_2$ in enough water to make 1.2 L of solution. What is the $[	ext{OH}^-]$ in the solution?

Accepted Answer

$[	ext{OH}^-] = 2 	imes \dfrac{0.25}{1.2}\ 	ext{M}$

Question 10

Which of the following is the correct formula to calculate the pOH of a solution given the $[	ext{OH}^-]$?

Accepted Answer

$	ext{pOH} = -\log([	ext{OH}^-])$

Question 11

A nurse needs to prepare 100 mL of a 0.10 M NaOH solution. How many grams of NaOH are required? (Molar mass of NaOH = 40.0 g/mol)

Accepted Answer

$0.40\ 	ext{g}$

Question 12

A 0.50 M solution of NH$_2^-$ is prepared. What is the $[	ext{OH}^-]$ in the solution, assuming complete dissociation?

Accepted Answer

$0.50\ 	ext{M}$

Question 13

If a solution has a pOH of 3.0, what is its pH at 25°C?

Accepted Answer

$	ext{pH} = 11.0$

Question 14

A laboratory technician accidentally mixes 0.10 M HCl and 0.10 M NaOH in equal volumes. What is the resulting pH of the mixture?

Accepted Answer

$	ext{pH} = 7.0$

Question 15

Which of the following best describes the relationship between the concentration of a strong base and the pOH of its solution?

Accepted Answer

As the concentration of the strong base increases, the pOH decreases.

Strong Acids, Strong Bases, and pH/pOH Calculations in GOB Chemistry

Study Guide - Practice Questions