$$pH = -\log(1 \times 10$$^{-5}$$) = 5$$

$$pK_a = -\log(1.8 \times 10$$^{-5}$$) \approx 4.74$$

$$pH = pK_a + \log \left( \frac{[\text{acetate}]}{[\text{acetic acid}]} \right)$$

Question 1

Which of the following best describes a Bronsted-Lowry acid?

Accepted Answer

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

Question 2

What is the conjugate base of H$$_2PO$_4^-$$?

Accepted Answer

HPO$$_4^{2-}$$

Question 3

A solution has [H$$_3O$^+$$] = $$1 	imes 10$$^{-5}$$ M. What is the pH of the solution?

Accepted Answer

$$pH = -\log(1 	imes 10$$^{-5}$$) = 5$$

Question 4

Which of the following statements about strong acids is correct?

Accepted Answer

Strong acids completely dissociate in water, so [H$$_3O$^+$$] equals the initial acid concentration.

Question 5

If the $$K_a$$ for acetic acid is $$1.8 	imes 10$$^{-5}$$, what is the pK_a$?

Accepted Answer

$$pK_a = -\log(1.8 	imes 10$$^{-5}$$) \approx 4.74$$

Question 6

Which of the following best explains why water can act as both an acid and a base?

Accepted Answer

Water can both donate and accept a proton (H$$^+$$), depending on the reaction partner.

Question 7

A buffer solution is prepared by mixing acetic acid and sodium acetate. Which equation best describes the pH of this buffer?

Accepted Answer

$$pH = pK_a + \log \left( \frac{[	ext{acetate}]}{[	ext{acetic acid}]} ight)$$

Question 8

Which of the following is a correct statement about polyprotic acids?

Accepted Answer

Polyprotic acids can donate more than one proton per molecule.

Question 9

A patient’s blood pH drops below 7.35. Which buffer system is most directly involved in compensating for this change?

Accepted Answer

The carbonic acid/bicarbonate buffer system

Question 10

If a solution has [OH$$^-$$] = $$1 	imes 10$$^{-3}$$ M, what is the pOH and pH of the solution?

Accepted Answer

$$pOH = 3$$, $$pH = 11$$

Question 11

Which of the following best describes what happens when HCl is added to water?

Accepted Answer

HCl donates a proton to water, forming H$$_3O$^+$$ and Cl$$^-$$

Question 12

Which of the following is true about the relationship between $$K_a$$ and $$pK_a$$?

Accepted Answer

As $$K_a$$ increases, $$pK_a$$ decreases, indicating a stronger acid.

Question 13

A buffer is most effective when:

Accepted Answer

The pH is close to the pK_a of the acid in the buffer

Question 14

Which of the following reactions represents the neutralization of a strong acid with a strong base?

Accepted Answer

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

Question 15

Which of the following best describes the role of the kidneys in acid-base balance?

Accepted Answer

They excrete excess acid or base and help regulate blood pH by controlling bicarbonate and hydrogen ion levels.

Question 16

If a weak acid has a $$K_a of$$ $$1 	imes 10$$^{-7}$$, which statement is true?

Accepted Answer

The acid is only partially dissociated in water.

Question 17

Which of the following is the correct Henderson-Hasselbalch equation for a weak acid and its conjugate base?

Accepted Answer

$$pH = pK_a + \log \left( \frac{[	ext{A}^-]}{[	ext{HA}]} ight)$$

Question 18

Which of the following is a symptom of acidosis in the human body?

Accepted Answer

Rapid, shallow breathing

Question 19

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

Accepted Answer

They resist changes in pH when small amounts of acid or base are added.

Acids, Bases, and Buffers: Principles and Biological Applications

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