$$[OH^-] = \frac{K_w}{[H_3O^+]} = \frac{1.00 \times 10$$^{-14}$$}{4.5 \times 10$$^{-7}$$} = 2.2 \times 10$$^{-8}$$ M

$$\text{pH} = \text{p}K_a + \log\left(\frac{[A^-]}{[HA]}\right)$$

Question 1

Which of the following statements best describes a Brønsted-Lowry acid?

Accepted Answer

A substance that donates a hydrogen ion (H+) to another molecule.

Question 2

Which of the following acids is diprotic?

Accepted Answer

H2SO4

Question 3

What is the conjugate base of HClO4?

Accepted Answer

ClO4–

Question 4

Which equation correctly represents the acid dissociation constant ($$K_a) $$for a weak acid HA in water?

Accepted Answer

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

Question 5

A solution has a hydronium ion concentration of $$4.5 	imes 10$$^{-7}$$ M. What is the hydroxide ion concentration?

Accepted Answer

$$[OH^-] = \frac{K_w}{[H_3O^+]} = \frac{1.00 	imes 10$$^{-14}$$}{4.5 	imes 10$$^{-7}$$} = 2.2 	imes 10$$^{-8}$$ M

Question 6

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

Accepted Answer

The stronger the acid, the weaker its conjugate base.

Question 7

What is the pH of a solution with $$[H_3O^+] = 1 	imes 10$$^{-5}$$ M?

Accepted Answer

pH = 5.0

Question 8

A buffer solution contains 0.100 M HF and 0.120 M NaF. The $$K_a of HF is$$ $$3.5 	imes 10$$^{-5}$$ (pK_a = 3.46$). What is the pH of the buffer?

Accepted Answer

pH = 3.46 + \log\left(\frac{0.120}{0.100}\right) = 3.54

Question 9

Which salt will produce a basic solution when dissolved in water?

Accepted Answer

NaCN

Question 10

A cleaning solution has $$[OH^-] = 1 	imes 10$$^{-3}$$ M. What is its pH?

Accepted Answer

pH = 11.0

Question 11

Which of the following is a correct net ionic equation for the neutralization of a strong acid with a strong base?

Accepted Answer

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

Question 12

Which equation represents the Henderson-Hasselbalch equation for buffer pH calculation?

Accepted Answer

$$	ext{pH} = 	ext{p}K_a + \log\left(\frac{[A^-]}{[HA]}ight)$$

Question 13

Which of the following best describes the role of a buffer in blood?

Accepted Answer

It prevents drastic changes in pH by neutralizing added acids or bases.

Question 14

If 0.020 mol of NaOH is added to 1.00 L of a buffer containing 0.100 M HF and 0.120 M F–, what will be the new concentrations of HF and F–?

Accepted Answer

[HF] = 0.080 M, [F–] = 0.140 M

Question 15

Which of the following is true about polyprotic acids?

Accepted Answer

The first dissociation occurs to nearly 100%, while subsequent dissociations are less complete.

Question 16

A 5.00 mL sample of vinegar is titrated with 44.5 mL of 0.100 M NaOH. What is the molarity of acetic acid in the vinegar?

Accepted Answer

0.890 M

Question 17

Which of the following is an amphoteric substance?

Accepted Answer

Water (H2O)

Question 18

Which of the following organic acids would be most appropriate for preparing a pH 4.15 buffer solution?

Accepted Answer

Ascorbic acid (pKa = 4.10)

Question 19

Which of the following best describes the result of adding a strong acid to a carbonate-containing rock?

Accepted Answer

Bubbles of CO2 gas are released.

Acids and Bases: Definitions, Strength, Equilibria, and Applications

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