Q: A solution is prepared by dissolving 0.20 M ammonium bromide (NH4Br) in water. Given that $$K_b$$ for ammonia is $$1.8 \times 10$$^{-5}$$, what is the K_a$ for the ammonium ion?

$$K_a = 5.6 \times 10$$^{-10}$$

Q: Given $$K_a$$ for acetic acid is $$1.8 \times 10$$^{-5}$$, what is the K_b$ for the acetate ion?

$$K_b = 5.6 \times 10$$^{-10}$$

Q: Which of the following is a correct expression for the percent ionization of a weak base $$B$$?

$$\frac{[OH^-]_{eq}}{[B]_i} \times 100$$

Question 1

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

Accepted Answer

The stronger the weak base, the weaker its conjugate acid.

Question 2

A solution is prepared by dissolving 0.20 M ammonium bromide (NH4Br) in water. Given that $$K_b$$ for ammonia is $$1.8 	imes 10$$^{-5}$$, what is the K_a$ for the ammonium ion?

Accepted Answer

$$K_a = 5.6 	imes 10$$^{-10}$$

Question 3

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

Accepted Answer

NaC2H3O2

Question 4

Calculate the pH of a 0.30 M dimethylamine $$((CH_3$)_2NH)$$ solution. $$K_b = 5.9 	imes 10$$^{-4}$$. Assume the approximation is valid.

Accepted Answer

pH = 12.11

Question 5

Which of the following is true about the pH of a solution containing both a weak acid and its conjugate base?

Accepted Answer

The pH depends on the relative concentrations and the $$K_a$$ and $$K_b$$ values.

Question 6

Given $$K_a$$ for acetic acid is $$1.8 	imes 10$$^{-5}$$, what is the K_b$ for the acetate ion?

Accepted Answer

$$K_b = 5.6 	imes 10$$^{-10}$$

Question 7

Which of the following best explains why NaF solution is basic?

Accepted Answer

F- hydrolyzes to produce OH-

Question 8

A 0.20 M solution of formic acid has a pH of 2.22. What is the percent ionization of formic acid in this solution?

Accepted Answer

3.0%

Question 9

Which of the following is the correct relationship between $$K_w$$, $$K_a$$, and $$K_b$$ for a conjugate acid-base pair?

Accepted Answer

$$K_w = K_a 	imes K_b$$

Question 10

Which of the following cations will NOT affect the pH of an aqueous solution?

Accepted Answer

Na+

Question 11

A salt solution contains both NH4+ and F-. If $$K_a(NH_4$^+) is$$ $$5.6 	imes 10$$^{-10}$$ and K_b(F$$^-)$$ is 1.5$$ 	imes $$10^{-11}$$, what is the expected pH of the solution?

Accepted Answer

Slightly acidic

Question 12

Which of the following is a correct expression for the percent ionization of a weak base $$B$$?

Accepted Answer

$$\frac{[OH^-]_{eq}}{[B]_i} 	imes 100$$

Question 13

Which of the following weak bases has the highest $$K_b$$ value at 25°C, based on the provided table?

Accepted Answer

Methylamine

Question 14

Which of the following is the correct formula for calculating the pH of a weak base solution after finding $$[OH^-]$$?

Accepted Answer

$$pH = 14.00 - pOH$$

Question 15

Which of the following anions is pH-neutral in water?

Accepted Answer

Cl-

Question 16

A solution is prepared by dissolving three aspirin tablets (pure acetylsalicylic acid, $$K_a = 3.30 	imes 10$$^{-4}$$, mw = 180.160$ g/mol, 325 mg each) in water to make 356 mL of solution. What is the initial molarity of the acid?

Accepted Answer

0.0152 M

Question 17

Which of the following best describes the effect of a small, highly charged metal ion (e.g., $$Al^{3+}) in a $$salt solution?

Accepted Answer

It makes the solution acidic by hydrolyzing water.

Question 18

Which of the following is the correct formula for calculating $$pK_b$$?

Accepted Answer

$$pK_b = -\log K_b$$

Question 19

Which of the following is a real-life application of acid-base chemistry discussed in the materials?

Accepted Answer

Calculating the pH of a solution prepared by dissolving aspirin tablets in water.

Acids, Bases, and the Properties of Salt Solutions: Advanced Concepts and Calculations

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