$\text{pH} = -\log(0.10) = 1.00$

$\text{pOH} = -\log(1.6 \times 10^{-3}) = 2.80$, $\text{pH} = 14 - 2.80 = 11.20$

$K_a = \frac{(1.6 \times 10^{-3})^2}{0.10 - 1.6 \times 10^{-3}} \approx 2.6 \times 10^{-5}$

$\text{pOH} = -\log(2.3 \times 10^{-3}) = 2.64$, $\text{pH} = 14 - 2.64 = 11.36$

$K_w = [H^+][OH^-] = 1.0 \times 10^{-14}$ at 25$^\circ$C

$x = \sqrt{(1.8 \times 10^{-5})(0.10)} = 1.34 \times 10^{-3}$, $\text{pH} = -\log(1.34 \times 10^{-3}) = 2.87$

Question 1

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

Accepted Answer

A substance that donates a proton (H$^+$) to another species.

Question 2

Which of the following is a strong acid?

Accepted Answer

HNO$_3$

Question 3

What is the conjugate base of HSO$_4^-$?

Accepted Answer

SO$_4^{2-}$

Question 4

A 0.10 M solution of HNO$_3$ has a pH closest to:

Accepted Answer

$	ext{pH} = -\log(0.10) = 1.00$

Question 5

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

Accepted Answer

NaF

Question 6

Calculate the pH of a 0.15 M NH$_3$ solution. ($K_b = 1.8 	imes 10^{-5}$)

Accepted Answer

$	ext{pOH} = -\log(1.6 	imes 10^{-3}) = 2.80$, $	ext{pH} = 14 - 2.80 = 11.20$

Question 7

Which of the following statements about strong acids is correct?

Accepted Answer

Their reaction equilibrium lies far to the right.

Question 8

What is the $K_a$ of a weak acid if a 0.10 M solution has a pH of 2.8?

Accepted Answer

$K_a = \frac{(1.6 	imes 10^{-3})^2}{0.10 - 1.6 	imes 10^{-3}} \approx 2.6 	imes 10^{-5}$

Question 9

Which of the following is an example of a Lewis acid?

Accepted Answer

BF$_3$

Question 10

Which of the following best explains why HF is a weak acid, while HCl is a strong acid?

Accepted Answer

HF has a stronger H–F bond, making it harder to ionize.

Question 11

A solution has $[OH^-] = 2.3 	imes 10^{-3}$ M. What is the pH?

Accepted Answer

$	ext{pOH} = -\log(2.3 	imes 10^{-3}) = 2.64$, $	ext{pH} = 14 - 2.64 = 11.36$

Question 12

Which of the following statements about the autoionization of water is correct?

Accepted Answer

$K_w = [H^+][OH^-] = 1.0 	imes 10^{-14}$ at 25$^\circ$C

Question 13

Which of the following is a correct net ionic equation for the neutralization of HCl with NaOH?

Accepted Answer

$H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)$

Question 14

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

Accepted Answer

$K_a 	imes K_b = K_w$

Question 15

A 0.10 M solution of acetic acid ($K_a = 1.8 	imes 10^{-5}$) is prepared. What is the approximate pH?

Accepted Answer

$x = \sqrt{(1.8 	imes 10^{-5})(0.10)} = 1.34 	imes 10^{-3}$, $	ext{pH} = -\log(1.34 	imes 10^{-3}) = 2.87$

Question 16

Which of the following best explains why NaCl is a neutral salt in water?

Accepted Answer

Both Na$^+$ and Cl$^-$ are the conjugates of strong acid/base and do not hydrolyze water.

Question 17

Which of the following is true for a polyprotic acid such as H$_2$SO$_4$?

Accepted Answer

The first ionization constant $K_{a1}$ is much larger than the second $K_{a2}$.

Ch 16: Acid-Base Equilibria: Models, Strengths, and Electrolytes

Study Guide - Practice Questions