Q: If the pK\_a of an acid is 3.5, what is its K\_a?

$$K\_a = 1.0 \times 10$$^{-3.5}$$

Question 1

Which of the following compounds is classified as a strong electrolyte in aqueous solution?

Accepted Answer

NaCl

Question 2

A student mixes solutions of Na\_2CO\_3 and HCl. Which gas is produced in the resulting reaction?

Accepted Answer

CO\_2

Question 3

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

Accepted Answer

NaNO\_2

Question 4

Given a solution with [H\_3O\^+] = $$1.0 	imes 10$$^{-4}$$ M, what is the pH of the solution?

Accepted Answer

$$pH = 4$$

Question 5

Which of the following is a correct net ionic equation for the reaction between acetic acid (CH\_3COOH) and sodium hydroxide (NaOH)?

Accepted Answer

$$CH\_3COOH + OH^- \rightarrow CH\_3COO^- + H\_2O$$

Question 6

A buffer is prepared using 0.10 M acetic acid (pK\_a = 4.76) and 0.10 M sodium acetate. What is the pH of the buffer?

Accepted Answer

$$pH = 4.76$$

Question 7

Which of the following statements about strong acids and their conjugate bases is correct?

Accepted Answer

The conjugate base of a strong acid is weak.

Question 8

Which compound is a weak base according to the Bronsted-Lowry definition?

Accepted Answer

NH\_3

Question 9

A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the volume of NaOH required to reach the equivalence point?

Accepted Answer

25.0 mL

Question 10

Which of the following compounds is insoluble in water according to the solubility rules?

Accepted Answer

BaSO\_4

Question 11

If the pK\_a of an acid is 3.5, what is its K\_a?

Accepted Answer

$$K\_a = 1.0 	imes 10$$^{-3.5}$$

Question 12

Which of the following best describes the purpose of an indicator in a titration?

Accepted Answer

To signal the endpoint by changing color.

Question 13

A buffer solution is made by mixing 0.20 mol of NH\_4Cl and 0.20 mol of NH\_3 in enough water to make 1.0 L. If the K\_b for NH\_3 is $$1.8 	imes 10$$^{-5}$$, what is the pH of the buffer? (Use pH = pK$$\_a + \log([A^-]/[HA])$$ and K$$\_w = 1.0 	imes $$10^{-14})$$

Accepted Answer

$$pH = 9.25$$

Question 14

Which of the following is a correct relationship between K\_a and K\_b for a conjugate acid-base pair?

Accepted Answer

$$K\_a 	imes K\_b = K\_w$$

Question 15

Which of the following titration curves would have an equivalence point at pH \u003e 7?

Accepted Answer

Weak acid titrated with strong base

Question 16

A solution is prepared by diluting 10.0 mL of 2.00 M NaOH to a final volume of 100.0 mL. What is the final concentration?

Accepted Answer

0.20 M

Question 17

Which of the following best describes buffer capacity?

Accepted Answer

The amount of acid or base a buffer can neutralize before pH changes significantly.

Question 18

Which of the following is a strong acid?

Accepted Answer

HCl

Question 19

Which of the following compounds is soluble in water according to the solubility rules?

Accepted Answer

K\_2SO\_4

Question 20

Which of the following statements about the autoionization of water is correct?

Accepted Answer

Water ionizes to produce equal concentrations of H\_3O\^+ and OH^- at 25°C.

General Chemistry II: Aqueous Reactions, Acid-Base Equilibria, Buffers, and Titrations

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