Question 1

A 0.10 M solution of LiBr is prepared in water. Which of the following best describes the pH of the solution?

Accepted Answer

The solution is neutral because both Li+ and Br- are spectator ions from a strong acid and a strong base.

Question 2

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

Accepted Answer

KClO2, because ClO2- is the conjugate base of a weak acid.

Question 3

Given $$K_a$$ for HCN is $$1.2 	imes 10$$^{-10}$$, what is the value of K_b$ for CN$$^-$$ at 25$$^\circ C$$? (Use K_w = 1.0$$ 	imes $$10^{-14})$$

Accepted Answer

$$K_b = 8.3 	imes 10$$^{-5}$$

Question 4

Which acid from the following list is the best candidate to prepare a buffer solution with a pH of 3.60?

Accepted Answer

HNO2

Question 5

A buffer solution is prepared by mixing acetic acid and sodium acetate. Which equation would you use to calculate the pH of this buffer?

Accepted Answer

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

Question 6

Why are buffer solutions important in biological systems?

Accepted Answer

They maintain a constant pH, which is crucial for enzyme activity and metabolic processes.

Question 7

5.0 mL of 2.0 M NaOH is added to 50.0 mL of pure water. What is the change in pH? (Assume complete dissociation and initial pH = 7.00)

Accepted Answer

The pH increases dramatically, becoming strongly basic.

Question 8

5.0 mL of 2.0 M NaOH is added to 50.0 mL of a buffer solution containing 0.45 M acetic acid and 0.65 M sodium acetate. What is the expected change in pH?

Accepted Answer

The pH increases only slightly due to the buffer's resistance to pH change.

Question 9

During the titration of 25 mL of 0.12 M HClO4 with 0.093 M KOH, what is the pH at the equivalence point?

Accepted Answer

pH = 7, because both the acid and base are strong.

Question 10

At the equivalence point in the titration of a weak acid with a strong base, the pH is:

Accepted Answer

Basic, because the conjugate base of the weak acid hydrolyzes to produce OH-.

Question 11

Which of the following best describes the titration curve for a strong acid with a strong base?

Accepted Answer

The pH rises sharply at the equivalence point, with a steep vertical region.

Question 12

Which equation describes the solubility of a gas in a liquid according to Henry's Law?

Accepted Answer

$$C = k_H P$$

Question 13

Given $$K_{sp}$$ for $$CaCO_3 is$$ $$4.5 	imes 10$$^{-9}$$, what is the molar solubility of $$CaCO_3$$ in pure water?

Accepted Answer

$$6.7 	imes 10$$^{-5}$$ \ M$$

Question 14

Which of the following best expresses the units of solubility for a solid in a liquid?

Accepted Answer

g/L or mol/L

Question 15

Which acid in the following list is the weakest?

Accepted Answer

HCN, because it has the smallest $$K_a$$ and largest $$pK_a.$$

Question 16

Which of the following salts is the least soluble in water?

Accepted Answer

Bi$$_2S$_3$$ ($$K_{sp} = 1.1 	imes 10$$^{-73}$$)

Question 17

A solution is prepared by dissolving 0.00019 g of AgCl in 100 mL of water. What does this value represent?

Accepted Answer

The solubility of AgCl in water at a given temperature.

Question 18

Which of the following statements about buffer solutions is correct?

Accepted Answer

A buffer resists changes in pH when small amounts of acid or base are added.

Question 19

Which of the following best explains why $$K_{sp}$$ values alone cannot always be used to compare the solubility of different salts?

Accepted Answer

Different salts dissociate into different numbers of ions, affecting the relationship between $$K_{sp}$$ and solubility.

General Chemistry Study Guide: Acids, Bases, Buffers, Titration, and Solubility

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