Q: Which of the following statements about the autoionization of water at 25$^\circ$C is correct?

The product $[\mathrm{H^+}][\mathrm{OH^-}]$ is $1.0 \times 10^{-14}$

Q: Which of the following is true for a strong acid in aqueous solution?

It fully dissociates, so $[\mathrm{H^+}] = [\text{acid added}]$

Question 1

Which of the following best describes a Lewis acid?

Accepted Answer

A substance that accepts an electron pair

Question 2

A solution is prepared by dissolving 0.10 M acetic acid ($\mathrm{CH_3COOH}$) in water. The $K_a$ for acetic acid is $1.8 	imes 10^{-5}$. What is the correct expression for the acid dissociation constant for this reaction?

Accepted Answer

$K_a = \frac{[\mathrm{H^+}][\mathrm{CH_3COO^-}]}{[\mathrm{CH_3COOH}]}$

Question 3

Which of the following statements about the autoionization of water at 25$^\circ$C is correct?

Accepted Answer

The product $[\mathrm{H^+}][\mathrm{OH^-}]$ is $1.0 	imes 10^{-14}$

Question 4

A 0.10 M solution of formic acid ($\mathrm{HCOOH}$) has a pH of 2.38 at 25$^\circ$C. What is the percent ionization of formic acid in this solution?

Accepted Answer

0.42\%

Question 5

Which of the following best explains why an aqueous solution of sodium chloride is essentially neutral, while an aqueous solution of iron(III) chloride is acidic?

Accepted Answer

Fe$^{3+}$ acts as a Lewis acid, increasing the tendency of coordinated water molecules to donate protons

Question 6

Which of the following is true for a strong acid in aqueous solution?

Accepted Answer

It fully dissociates, so $[\mathrm{H^+}] = [	ext{acid added}]$

Question 7

A solution has $[\mathrm{OH^-}] = 1.0 	imes 10^{-3}\ \mathrm{M}$ at 25$^\circ$C. What is the pH of the solution?

Accepted Answer

pH = 11.00

Question 8

Which of the following best describes the relationship between acid strength and conjugate base strength?

Accepted Answer

The stronger the acid, the weaker its conjugate base

Question 9

Which of the following is the correct formula for calculating the pH of a solution?

Accepted Answer

$\mathrm{pH} = -\log[\mathrm{H^+}]$

Question 10

A 0.30 M solution of acetic acid ($K_a = 1.8 	imes 10^{-5}$) is prepared. Which of the following is the correct setup to find the pH using an ICE table?

Accepted Answer

Set initial $[\mathrm{CH_3COOH}] = 0.30\ \mathrm{M}$, $[\mathrm{H^+}] = 0$, $[\mathrm{CH_3COO^-}] = 0$; let $x$ be the amount dissociated, then $K_a = \frac{x^2}{0.30 - x}$

Question 11

Which of the following factors increases the acidity of a binary acid $\mathrm{H-A}$?

Accepted Answer

Increasing the electronegativity of A

Question 12

Which of the following statements about polyprotic acids is correct?

Accepted Answer

Each successive proton is more difficult to remove, so $K_{a1} > K_{a2}$

Question 13

A household bleach solution contains sodium hypochlorite (NaOCl). Which statement best explains why the solution is basic?

Accepted Answer

OCl$^-$ is a weak base that reacts with water to produce OH$^-$

Question 14

Which of the following is the correct relationship between $K_a$ and $K_b$ for a conjugate acid-base pair at 25$^\circ$C?

Accepted Answer

$K_a 	imes K_b = K_w = 1.0 	imes 10^{-14}$

Question 15

Which of the following best describes an amphiprotic substance?

Accepted Answer

A substance that can act as both a Bronsted-Lowry acid and base

Question 16

A solution at 25$^\circ$C has a pH of 4.00. What is the concentration of $\mathrm{H^+}$ in this solution?

Accepted Answer

$1.0 	imes 10^{-4}\ \mathrm{M}$

Question 17

Which of the following is a correct statement about the pH and pOH of a solution at 25$^\circ$C?

Accepted Answer

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

Question 18

Which of the following best explains why the acidity of metal cations increases with charge?

Accepted Answer

Cations with higher charge can more easily accept electron pairs from water, increasing hydrolysis

Acid-Base Equilibria: Definitions, Properties, and Applications

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