Question 1

Which of the following best describes a Lewis acid?

Accepted Answer

A substance that accepts an electron pair in a chemical reaction.

Question 2

Which of the following statements about the relationship between acid strength and conjugate base strength is correct?

Accepted Answer

The stronger the acid, the weaker its conjugate base.

Question 3

A solution has a pH of 3.5. Which of the following statements is true?

Accepted Answer

The solution is acidic because pH is below 7.

Question 4

Which of the following is an example of an amphiprotic substance?

Accepted Answer

H2O

Question 5

Given the reaction: $$\mathrm{HF} + \mathrm{H_2O} \rightleftharpoons \mathrm{F^-} + \mathrm{H_3O^+}$$, which pair represents a conjugate acid-base pair?

Accepted Answer

$$\mathrm{HF}$$ and $$\mathrm{F^-}$$

Question 6

What is the value of $$[\mathrm{H^+}] in a $$solution with pH = 4.25?

Accepted Answer

$$1.8 	imes 10$$^{-5}$$ M

Question 7

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

Accepted Answer

NaF

Question 8

A 0.10 M solution of a weak acid, HA, has a pH of 3.0. What is the percent ionization of the acid?

Accepted Answer

1.0%

Question 9

Which of the following factors increases the strength of a binary acid HX?

Accepted Answer

Decreasing the bond strength between H and X.

Question 10

Which of the following is the correct expression for the acid dissociation constant, $$K_a$$, for acetic acid ($$\mathrm{CH_3COOH}$$)?

Accepted Answer

$$K_a = \frac{[\mathrm{CH_3COO^-}][\mathrm{H^+}]}{[\mathrm{CH_3COOH}]}$$

Question 11

Which of the following statements about polyprotic acids is correct?

Accepted Answer

The first dissociation constant, $$K_{a1}$$, is always larger than the second, $$K_{a2}.$$

Question 12

Which of the following best explains why transition metal cations often make aqueous solutions acidic?

Accepted Answer

They act as Lewis acids, accepting electron pairs from water molecules.

Question 13

If the $$K_a$$ for a weak acid is $$1.8 	imes 10$$^{-5}$$ and the K_b$ for its conjugate base is 5.6$$ 	imes $$10^{-10}$$, what is the value of $$K_w at $$this temperature?

Accepted Answer

$$1.0 	imes 10$$^{-14}$$

Question 14

Which of the following is a correct statement about the pH and pOH of a neutral solution at 25°C?

Accepted Answer

$$\mathrm{pH} = 7$$ and $$\mathrm{pOH} = 7$$

Question 15

Which of the following best describes the behavior of a strong acid in aqueous solution?

Accepted Answer

It completely dissociates into ions.

Question 16

A 0.20 M solution of a weak base has a pOH of 4.7. What is the $$[\mathrm{OH^-}] in $$the solution?

Accepted Answer

$$2.0 	imes 10$$^{-5}$$ M

Question 17

Which of the following factors contributes to the acidity of carboxylic acids?

Accepted Answer

The resonance stabilization of the carboxylate anion.

Question 18

Which of the following is the correct relationship between pH and $$[\mathrm{H^+}]$$?

Accepted Answer

$$\mathrm{pH} = -\log_{10}[\mathrm{H^+}]$$

Question 19

Which of the following statements about the hydrolysis of salts is correct?

Accepted Answer

Anions of weak acids hydrolyze to form basic solutions.

Acid–Base Equilibria: Classification, Strength, and Calculations

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