Q: A solution has a pH of 4. What is the $$[\mathrm{H_3O^+}]$$ concentration?

$$1 \times 10$$^{-4}$$\ \mathrm{M}$$

Q: A student titrates 25.00 mL of HCl with 0.200 M NaOH. It takes 30.00 mL of NaOH to reach the equivalence point. What is the concentration of the HCl solution?

$$0.200\ \mathrm{M} \times \frac{30.00\ \mathrm{mL}}{25.00\ \mathrm{mL}} = 0.240\ \mathrm{M}$$

Question 1

Which of the following statements best explains why gold is used for James Bond's acid-filled pen in spy movies?

Accepted Answer

Gold is one of the few metals that is not dissolved by most acids.

Question 2

Which of the following is a property of bases, but NOT acids?

Accepted Answer

They feel slippery to the touch.

Question 3

According to the Arrhenius definition, which of the following is classified as a base?

Accepted Answer

NaOH, because it produces $$\mathrm{OH^-}$$ ions in water.

Question 4

Which of the following equations represents the self-ionization of water?

Accepted Answer

$$\mathrm{H_2O(l) + H_2O(l) \rightleftharpoons H_3O^+(aq) + OH^-(aq)}$$

Question 5

A solution has a pH of 4. What is the $$[\mathrm{H_3O^+}]$$ concentration?

Accepted Answer

$$1 	imes 10$$^{-4}$$\ \mathrm{M}$$

Question 6

Which of the following best describes a buffer solution?

Accepted Answer

A solution that contains a weak acid and its conjugate base.

Question 7

What is the balanced net ionic equation for the neutralization of HCl(aq) with NaOH(aq)?

Accepted Answer

$$\mathrm{H^+(aq) + OH^-(aq) \rightarrow H_2O(l)}$$

Question 8

Which of the following is a weak acid?

Accepted Answer

HF

Question 9

A student titrates 25.00 mL of HCl with 0.200 M NaOH. It takes 30.00 mL of NaOH to reach the equivalence point. What is the concentration of the HCl solution?

Accepted Answer

$$0.200\ \mathrm{M} 	imes \frac{30.00\ \mathrm{mL}}{25.00\ \mathrm{mL}} = 0.240\ \mathrm{M}$$

Question 10

Which of the following best explains why strong acids are also strong electrolytes?

Accepted Answer

They completely ionize in solution, producing many ions.

Question 11

Which of the following reactions is an example of an acid reacting with a metal to produce hydrogen gas?

Accepted Answer

$$\mathrm{2HCl(aq) + Mg(s) \rightarrow H_2$(g) + $$MgCl_2$$(aq)}$$

Question 12

Which of the following statements about the pH scale is correct?

Accepted Answer

A decrease of 1 unit on the pH scale corresponds to a tenfold increase in $$[\mathrm{H_3O^+}].$$

Question 13

Which of the following is the correct formula for the ion product constant for water ($$K_w) at 25$$°C?

Accepted Answer

$$K_w = [\mathrm{H_3O^+}] 	imes [\mathrm{OH^-}]$$

Question 14

A solution has $$[\mathrm{OH^-}] = 1 	imes 10$$^{-9}$$\ \mathrm{M}. $$What is the pH of the solution at 25°C?

Accepted Answer

pH = 5

Question 15

Which of the following best describes an amphoteric substance?

Accepted Answer

A substance that can act as either an acid or a base.

Question 16

Which of the following is a conjugate acid-base pair?

Accepted Answer

NH$$_3$$ and NH$$_4^+$$

Question 17

A buffer solution is prepared using acetic acid and sodium acetate. What happens when a small amount of HCl is added to this buffer?

Accepted Answer

The acetate ion reacts with the added HCl, minimizing the pH change.

Question 18

Which of the following is a real-world example of a buffer system?

Accepted Answer

Human blood

Question 19

Which of the following best explains why sodium bicarbonate (baking soda) can relieve heartburn?

Accepted Answer

It is a weak base that neutralizes excess stomach acid.

Acids and Bases: Properties, Reactions, and Quantitative Analysis

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