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

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

Question 1

Which of the following statements best describes the relationship between the acid dissociation constant ($$K_a) of a $$weak acid and the base dissociation constant ($$K_b) of $$its conjugate base?

Accepted Answer

$$K_w = K_a 	imes K_b$$

Question 2

A 0.20 M solution of formic acid ($$HCHO_2) $$has a pH of 2.22. What is the percent ionization of formic acid in this solution?

Accepted Answer

3.0%

Question 3

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

Accepted Answer

NaCHO$$_2$$

Question 4

Given $$K_b$$ for ammonia ($$NH_3) is$$ $$1.8 	imes 10$$^{-5}$$, what is the K_a$ for its conjugate acid (NH_4$^+$$)?

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

A solution of 0.10 M NaOH has a pOH of 1.00. What is the pH of this solution?

Accepted Answer

13.00

Question 7

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

Accepted Answer

Na$$^+$$

Question 8

Calculate the pH of a 0.20 M solution of ammonium bromide ($$NH_4Br$$), given $$K_b$$ for ammonia is $$1.8 	imes 10$$^{-5}$$.

Accepted Answer

4.96

Question 9

Which of the following statements is true regarding the strength of a weak base and its conjugate acid?

Accepted Answer

The stronger the base, the weaker its conjugate acid.

Question 10

A 0.30 M solution of dimethylamine ($$ (CH_3$)_2NH ) $$has $$K_b = 5.9 	imes 10$$^{-4}$$. What is the pH of this solution?

Accepted Answer

12.11

Question 11

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

Accepted Answer

Cl$$^-$$

Question 12

If a salt solution contains a cation from a weak base and an anion from a weak acid, what determines whether the solution is acidic, basic, or neutral?

Accepted Answer

The relative values of $$K_a$$ and $$K_b$$

Question 13

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

Accepted Answer

$$pOH = -\log[OH^-]$$

Question 14

A solution is prepared by dissolving three aspirin tablets (each containing 325 mg of acetylsalicylic acid, $$HC_9H_7O_4) in $$water to make 356 mL of solution. The $$K_a of $$acetylsalicylic acid is $$3.3 	imes 10$$^{-4}$$. What is the initial molarity of the acid in the solution?

Accepted Answer

0.0152 M

Question 15

Which of the following best explains why the quadratic equation must sometimes be used in weak acid or base calculations?

Accepted Answer

When the percent ionization is greater than 5%

Question 16

Which of the following weak bases has the largest $$K_b$$ value at 25°C, according to the provided table?

Accepted Answer

Methylamine ($$CH_3NH_2)$$

Question 17

Which of the following is a correct statement about the pH of a solution of $$NH_4F ($$ammonium fluoride)?

Accepted Answer

The solution is slightly acidic because $$K_a \u003e K_b$$

Question 18

Which of the following is the correct relationship between $$pK_w$$, $$pK_a$$, and $$pK_b$$?

Accepted Answer

$$pK_w = pK_a + pK_b$$

Question 19

A solution of sodium formate ($$NaCHO_2) is $$prepared at 0.20 M. Given $$K_a$$ for formic acid is $$1.8 	imes 10$$^{-4}$$, what is the pH of the solution?

Accepted Answer

8.52

Acids, Bases, and the Properties of Salt Solutions

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