Question 1

Which of the following best describes why water is considered an amphiprotic substance?

Accepted Answer

Because it can act as both an acid and a base depending on the reactant.

Question 2

Given $$[OH^-] = 5.0 	imes 10$$^{-8}$$ \ M$$, what is the $$[H_3O^+] in $$the solution at 25°C? (Use $$K_w = 1.0 	imes 10$$^{-14}$$)

Accepted Answer

$$2.0 	imes 10$$^{-7}$$ \ M$$

Question 3

Which of the following solutions is considered basic?

Accepted Answer

$$[H_3O^+] \u003c [OH^-]$$

Question 4

A solution has $$[H_3O^+] = 1.7 	imes 10$$^{-3}$$ \ M. $$What is its pH?

Accepted Answer

pH = $$2.77$$

Question 5

Which of the following equations correctly represents the neutralization reaction between hydrochloric acid and sodium hydroxide?

Accepted Answer

$$HCl (aq) + NaOH (aq) \rightarrow H_2O (l) + NaCl (aq)$$

Question 6

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

They maintain a relatively constant pH when small amounts of acid or base are added.

Question 7

What is the $$[H_3O^+]$$ for a solution with a pH of 3.42?

Accepted Answer

$$3.8 	imes 10$$^{-4}$$ \ M$$

Question 8

Which of the following is a correct statement about the pH scale?

Accepted Answer

A solution with pH 2 has one hundred times more $$[H_3O^+]$$ than a solution with pH 4.

Question 9

Which of the following combinations would create a buffer solution?

Accepted Answer

Acetic acid ($$HC_2H_3O_2) $$and sodium acetate ($$NaC_2H_3O_2)$$

Question 10

A buffer solution contains a large amount of $$HC_2H_3O_2$$ and $$C_2H_3O_2^-. $$What happens when a small amount of acid is added?

Accepted Answer

The added $$H_3O^+$$ combines with $$C_2H_3O_2^-$$, shifting equilibrium to the reactants and maintaining pH.

Question 11

Which of the following best describes the role of a conjugate base in a buffer solution?

Accepted Answer

It reacts with added $$H_3O^+ to $$minimize changes in pH.

Question 12

Which of the following is the correct balanced equation for the reaction of hydrochloric acid with barium hydroxide?

Accepted Answer

$$2HCl (aq) + Ba(OH)_2 (s) \rightarrow 2H_2O (l) + $$BaCl_2$$ (aq)$$

Question 13

A patient’s blood pH drops to 7.1. Which of the following best describes what happens to the buffer system in their blood?

Accepted Answer

The buffer system will attempt to neutralize excess acid to restore pH toward normal.

Question 14

Which of the following is true about the relationship between $$[H_3O^+]$$ and pH?

Accepted Answer

As $$[H_3O^+]$$ increases, pH decreases.

Question 15

Which of the following best describes what happens when a small amount of base is added to a buffer solution containing acetic acid and acetate?

Accepted Answer

The base is neutralized by acetic acid, and the pH changes only slightly.

Question 16

Which of the following is the correct formula for calculating pH from $$[H_3O^+]$$?

Accepted Answer

$$pH = -\log [H_3O^+]$$

Question 17

A solution has a pH of 8. What is the $$[H_3O^+]$$?

Accepted Answer

$$1.0 	imes 10$$^{-8}$$ \ M$$

Question 18

Which of the following is a real-life example of the importance of buffers?

Accepted Answer

Maintaining blood pH within a narrow range for proper enzyme function.

Water, pH, and Reactions of Acids and Bases: Study Notes

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