Q: What is the pH of a solution with [H$_3$O$^+$] = $1.0 \times 10^{-4}$ M?

$pH = -\log(1.0 \times 10^{-4}) = 4$

Q: Which of the following is true about the relationship between [H$_3$O$^+$] and [OH$^-$] in pure water at 25$^\circ$C?

$[H_3O^+] = [OH^-] = 1.0 \times 10^{-7}$ M$

Q: If the pH of blood is 7.4, what is the concentration of hydronium ions ([H$_3$O$^+$]) in blood?

$[H_3O^+] = 4.0 \times 10^{-8}$ M$

Q: A solution has [OH$^-$] = $1.0 \times 10^{-3}$ M. What is the pH of the solution?

$pOH = -\log(1.0 \times 10^{-3}) = 3$, so pH = 14 - 3 = 11$

Q: Calculate the pH of a solution with [H$_3$O$^+$] = $2.5 \times 10^{-5}$ M.

$pH = -\log(2.5 \times 10^{-5}) = 4.60$

Question 1

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

Accepted Answer

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

Question 2

What is the pH of a solution with [H$_3$O$^+$] = $1.0 	imes 10^{-4}$ M?

Accepted Answer

$pH = -\log(1.0 	imes 10^{-4}) = 4$

Question 3

Which of the following is true about the relationship between [H$_3$O$^+$] and [OH$^-$] in pure water at 25$^\circ$C?

Accepted Answer

$[H_3O^+] = [OH^-] = 1.0 	imes 10^{-7}$ M$

Question 4

A buffer solution is made by mixing acetic acid (CH$_3$COOH) and sodium acetate (CH$_3$COONa). Which equation can be used to calculate its pH?

Accepted Answer

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

Question 5

If the pH of blood is 7.4, what is the concentration of hydronium ions ([H$_3$O$^+$]) in blood?

Accepted Answer

$[H_3O^+] = 4.0 	imes 10^{-8}$ M$

Question 6

Which of the following is an example of an amphiprotic substance?

Accepted Answer

HCO$_3^-$

Question 7

A solution has [OH$^-$] = $1.0 	imes 10^{-3}$ M. What is the pH of the solution?

Accepted Answer

$pOH = -\log(1.0 	imes 10^{-3}) = 3$, so pH = 14 - 3 = 11$

Question 8

Which of the following best describes the direction of an acid-base equilibrium?

Accepted Answer

It favors the reaction of the stronger acid with the stronger base, forming the weaker acid and weaker base.

Question 9

What is the value of the ion product constant for water ($K_w$) at 25$^\circ$C?

Accepted Answer

$K_w = 1.0 	imes 10^{-14}$

Question 10

Which of the following is the correct expression for the acid dissociation constant ($K_a$) for the reaction $HA(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + A^-(aq)$?

Accepted Answer

$K_a = \frac{[H_3O^+][A^-]}{[HA]}$

Question 11

A buffer is most effective when:

Accepted Answer

The concentrations of the weak acid and its conjugate base are nearly equal.

Question 12

Which of the following salts will produce a basic solution when dissolved in water?

Accepted Answer

NaCH$_3$COO (sodium acetate)

Question 13

Calculate the pH of a solution with [H$_3$O$^+$] = $2.5 	imes 10^{-5}$ M.

Accepted Answer

$pH = -\log(2.5 	imes 10^{-5}) = 4.60$

Question 14

Which of the following is true about strong acids?

Accepted Answer

They completely dissociate in water.

Question 15

A solution contains 0.10 M HCl. What is the [OH$^-$] in this solution?

Accepted Answer

$[OH^-] = \frac{K_w}{[H_3O^+]} = \frac{1.0 	imes 10^{-14}}{0.10} = 1.0 	imes 10^{-13}$ M$

Question 16

Which equation is used to relate the normality (N) of an acid to the equivalents and volume?

Accepted Answer

$N = \frac{	ext{Equivalents of acid or base}}{	ext{Liters of solution}}$

Question 17

During a titration, if $M_{acid}V_{acid} = M_{base}V_{base}$, what does this indicate?

Accepted Answer

The moles of acid and base are equal at the equivalence point.

Question 18

Which of the following buffer systems is important in blood?

Accepted Answer

HCO$_3^-$ / H$_2$CO$_3$

Question 19

Which of the following is the correct Henderson-Hasselbalch equation for a buffer?

Accepted Answer

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

Acids and Bases: Principles, Calculations, and Applications

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