$$\mathrm{pH} = \mathrm{p}K_a + \log \frac{[\text{conjugate base}]}{[\text{acid}]}$$

Question 1

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

Accepted Answer

A substance that donates a proton (H+)

Question 2

What is the conjugate base of HCO3$$^- ($$bicarbonate)?

Accepted Answer

CO3$$^{2-}$$

Question 3

Calculate the pH of a solution with [H3O$$^+$$] = 1 	imes $$10^{-6}$$ 	ext{ M}.

Accepted Answer

6

Question 4

If the pH of a solution is 3, what is the pOH at 25$$^\circC$$?

Accepted Answer

11

Question 5

Which of the following acids is the strongest based on pKa values?

Accepted Answer

Nitrous Acid (HNO2), pKa = 3.33

Question 6

What are the products of the reaction: NaHCO3 + CH3COOH → ?

Accepted Answer

NaCH3COO + H2O + CO2

Question 7

A buffer solution is prepared with acetic acid (pKa = 4.74) and sodium acetate. If the pH is 5.74, what is the ratio of [CH3COO$$^-$$] to [CH3COOH]?

Accepted Answer

10:1

Question 8

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

Accepted Answer

They excrete excess H+ and reabsorb HCO3$$^-$$

Question 9

A patient is hyperventilating. What acid-base disturbance is most likely to occur?

Accepted Answer

Respiratory alkalosis

Question 10

Which of the following is true about buffers?

Accepted Answer

They are most effective when pH = pKa ± 1

Question 11

What is the pH of a 0.001 M HBr solution?

Accepted Answer

3

Question 12

Which of the following is a product of a neutralization reaction between HCl and NaOH?

Accepted Answer

NaCl and H2O

Question 13

If the pKa of a functional group in a blood protein is 5.5, what is its protonation state at pH 7.4?

Accepted Answer

Mostly deprotonated

Question 14

Which of the following is NOT a major buffer system in the human body?

Accepted Answer

Sodium chloride

Question 15

A patient has decreased respiratory rate due to hypothermia. How is homeostasis affected?

Accepted Answer

Respiratory acidosis

Question 16

Which equation correctly relates pH, pKa, and the ratio of conjugate base to acid?

Accepted Answer

$$\mathrm{pH} = \mathrm{p}K_a + \log \frac{[	ext{conjugate base}]}{[	ext{acid}]}$$

Question 17

Which of the following best describes what happens to the pH of carbonic acid-bicarbonate buffered blood (pH = 7.4) when some acid (H+) is added?

Accepted Answer

pH decreases slightly

Question 18

Which of the following is true for a strong acid in water?

Accepted Answer

It completely dissociates, so [H3O$$^+$$] equals the acid concentration

Question 19

Which of the following best describes the effect of adding a strong base to a buffer solution containing acetic acid and acetate?

Accepted Answer

The pH increases slightly

Question 20

Which of the following is the strongest base, given the pKa values of their conjugate acids?

Accepted Answer

Carbonate (CO3$$^{2-}$$), pKa = 10.25

Lecture 4: Acids, Bases and Buffers in Biological Systems

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