Q: A solution has $$[\mathrm{H}^+] = 2.0 \times 10$$^{-6}$$\ \mathrm{M} at$$ $$25^\circ\mathrm{C}. $$What is $$[\mathrm{OH}^-] in $$this solution?

$$5.0 \times 10$$^{-9}$$\ \mathrm{M}$$

Q: Fresh apple juice has a $$pOH = 10.24. $$What is the $$[\mathrm{H}^+] in $$this solution?

$$1.7 \times 10$$^{-4}$$\ \mathrm{M}$$

Question 1

Which of the following best describes the Brønsted–Lowry definition of an acid?

Accepted Answer

A substance that donates a proton (H+) to another substance.

Question 2

Given the reaction: $$\mathrm{HCl}(aq) + \mathrm{NH}_3(aq) \rightarrow \mathrm{Cl}^-(aq) + \mathrm{NH}_4^+(aq)$$, which species acts as the Brønsted–Lowry base?

Accepted Answer

$$\mathrm{NH}_3$$

Question 3

Which of the following is true about the autoionization of water?

Accepted Answer

It produces equal concentrations of $$\mathrm{H}_3\mathrm{O}^+$$ and $$\mathrm{OH}^- in $$pure water.

Question 4

Calculate the pH of a $$0.040\ \mathrm{M}$$ solution of $$\mathrm{HClO}_4 (a $$strong acid) at $$25^\circ\mathrm{C}.$$

Accepted Answer

$$pH = 1.40$$

Question 5

Which of the following acids is classified as a weak acid based on the acid strength chart?

Accepted Answer

$$\mathrm{CH}_3\mathrm{COOH}$$

Question 6

A solution has $$[\mathrm{H}^+] = 2.0 	imes 10$$^{-6}$$\ \mathrm{M} at$$ $$25^\circ\mathrm{C}. $$What is $$[\mathrm{OH}^-] in $$this solution?

Accepted Answer

$$5.0 	imes 10$$^{-9}$$\ \mathrm{M}$$

Question 7

Which of the following statements about conjugate acid-base pairs is correct?

Accepted Answer

A strong acid has a weak conjugate base.

Question 8

What is the $$pOH of a $$solution with $$[\mathrm{OH}^-] = 1.0 	imes 10$$^{-3}$$\ \mathrm{M}$$?

Accepted Answer

$$pOH = 3.00$$

Question 9

Which of the following is the correct relationship between $$K_a$$ and $$K_b$$ for a conjugate acid-base pair?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 10

A $$0.10\ \mathrm{M}$$ solution of formic acid ($$\mathrm{HCOOH}) $$has a pH of $$2.38 at$$ $$25^\circ\mathrm{C}. $$What is the $$K_a$$ for formic acid at this temperature?

Accepted Answer

$$1.7 	imes 10$$^{-4}$$

Question 11

Which of the following is a polyprotic acid?

Accepted Answer

$$\mathrm{H}_2\mathrm{SO}_3$$

Question 12

Which of the following best describes the Lewis definition of a base?

Accepted Answer

A substance that donates an electron pair.

Question 13

What is the pH of a $$0.0011\ \mathrm{M}$$ solution of $$\mathrm{Ca(OH)}_2 at$$ $$25^\circ\mathrm{C}$$? (Assume complete dissociation.)

Accepted Answer

$$pH = 11.64$$

Question 14

Which of the following is the correct formula for calculating pH?

Accepted Answer

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

Question 15

A $$0.30\ \mathrm{M}$$ acetic acid solution has $$K_a = 1.8 	imes 10$$^{-5}$$ at 25$$^\circ\mathrm{C}$$. What is the approximate pH of this solution?

Accepted Answer

$$pH = 2.22$$

Question 16

Which of the following is a strong base?

Accepted Answer

$$\mathrm{KOH}$$

Question 17

A $$0.15\ \mathrm{M}$$ solution of $$\mathrm{NH}_3$$ has $$K_b = 1.8 	imes 10$$^{-5}$$ at 25$$^\circ\mathrm{C}$$. What is the pH of this solution?

Accepted Answer

$$pH = 11.2$$

Question 18

Which of the following best describes water ($$\mathrm{H}_2\mathrm{O}) in $$acid-base chemistry?

Accepted Answer

It is amphiprotic, acting as either an acid or a base.

Question 19

Fresh apple juice has a $$pOH = 10.24. $$What is the $$[\mathrm{H}^+] in $$this solution?

Accepted Answer

$$1.7 	imes 10$$^{-4}$$\ \mathrm{M}$$

Acid-Base Equilibria: Classification, Strength, and Calculations

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