Question 1

Which of the following best describes the function of a buffer solution in the human body, as illustrated by the blood pH in the first image?

Accepted Answer

A buffer solution maintains a constant pH by neutralizing added acids or bases.

Question 2

Given a buffer solution containing 0.14 M HF (pKa = 3.15) and 0.071 M KF, what is the pH of the solution? Use the Henderson-Hasselbalch equation.

Accepted Answer

$$2.41$$

Question 3

Which combination of chemicals would create a buffer solution, as shown in the third image?

Accepted Answer

NH$$_3$$ and NH$$_4Cl$$

Question 4

A buffer is most effective when the concentrations of acid and base are:

Accepted Answer

Equal to each other

Question 5

Which of the following actions would destroy a buffer made of 0.050 M HC$$_2H$_3O$_2$$ and 0.250 M NaC$$_2H$_3O$_2 in 1.0 L $$solution?

Accepted Answer

Adding 0.050 moles of HCl

Question 6

During the titration of a strong acid with a strong base, what is the pH at the equivalence point?

Accepted Answer

$$7.0$$

Question 7

Which point on a titration curve of a weak acid with a strong base corresponds to the buffer region?

Accepted Answer

Before the equivalence point, where pH changes slowly

Question 8

What is the molar solubility of AgCl in pure water at 25°C if $$K_{sp} = 1.77 	imes 10$$^{-10}$$?

Accepted Answer

$$1.33 	imes 10$$^{-5}$$ M

Question 9

If the solubility product constant ($$K_{sp}) $$for PbBr$$_2 is$$ $$4.63 	imes 10$$^{-6}$$, what is the molar solubility of PbBr_2$ in pure water?

Accepted Answer

$$1.05 	imes 10$$^{-2}$$ M

Question 10

Which of the following will increase the solubility of AgCl in water?

Accepted Answer

Adding NH$$_3 to $$form a complex ion with Ag$$^+$$

Question 11

A solution is supersaturated with sodium acetate. What will happen if a seed crystal is added, as shown in the image?

Accepted Answer

Solid sodium acetate will rapidly precipitate out.

Question 12

Which of the following statements about the effect of a common ion on solubility is correct?

Accepted Answer

The addition of a common ion decreases the solubility of an ionic compound.

Question 13

Which acid would be the best choice to combine with its conjugate base to make a buffer with pH = 4.55?

Accepted Answer

HB; $$pK_a = 4.25$$

Question 14

What is the effect on the pH of a buffer solution if a small amount of strong acid is added?

Accepted Answer

The pH decreases slightly, but the buffer resists large changes.

Question 15

Which of the following best explains why a concentrated buffer can neutralize more added acid or base than a dilute buffer?

Accepted Answer

A concentrated buffer contains more moles of acid and base to react with added acid or base.

Question 16

Which of the following is true for the titration of 10.0 mL of 0.100 M HCl with 0.100 M NaOH compared to the titration of 10.0 mL of 0.100 M HF with 0.100 M NaOH?

Accepted Answer

Both titrations require the same volume of titrant to reach the first equivalence point.

Question 17

What is the correct expression for the solubility product constant ($$K_{sp}) $$for PbCl$$_2$$?

Accepted Answer

$$K_{sp} = [Pb$$^{2+}$$][Cl^-]^2$$

Question 18

If $$K_{sp}$$ for Mg(OH)$$_2 is$$ $$2.06 	imes 10$$^{-13}$$, what is the molar solubility of Mg(OH)_2$ in pure water?

Accepted Answer

$$3.72 	imes 10$$^{-5}$$ M

Question 19

Which of the following best describes what happens at the equivalence point during the titration of a weak acid with a strong base?

Accepted Answer

All the weak acid has been neutralized, and the solution contains only the conjugate base.

Chapter 18: Ionic Equilibrium – Buffers, Titrations, and Solubility

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