$$\text{pH} = -\log(0.10) = 1.00$$

$$\text{pOH} = -\log(1.6 \times 10$$^{-3}$$) = 2.80$$, $$\text{pH} = 14 - 2.80 = 11.20$$

$$K_a = \frac{(1.6 \times 10$$^{-3}$$)^2$$}{0.10 - 1.6 \times $$10^{-3}$$} \approx 2.6 \times $$10^{-5}$

$$\text{pOH} = -\log(2.3 \times 10$$^{-3}$$) = 2.64$$, $$\text{pH} = 14 - 2.64 = 11.36$$

$$K_w = [H^+][OH^-] = 1.0 \times 10$$^{-14}$$ at 25$$^\circ$$C

$$x = \sqrt{(1.8 \times 10$$^{-5}$$)(0.10)} = 1.34 \times 10$$^{-3}$$, $$\text{pH} = -\log(1.34 \times $$10^{-3}) = 2.87$

Question 1

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

Accepted Answer

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

Question 2

Which of the following is a strong acid?

Accepted Answer

HNO$$_3$$

Question 3

What is the conjugate base of HSO$$_4^-$$?

Accepted Answer

SO$$_4$$^{2-}$$

Question 4

A 0.10 M solution of HNO$$_3$$ has a pH closest to:

Accepted Answer

$$	ext{pH} = -\log(0.10) = 1.00$$

Question 5

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

Accepted Answer

NaF

Question 6

Calculate the pH of a 0.15 M NH$$_3$$ solution. ($$K_b = 1.8 	imes 10$$^{-5}$$)

Accepted Answer

$$	ext{pOH} = -\log(1.6 	imes 10$$^{-3}$$) = 2.80$$, $$	ext{pH} = 14 - 2.80 = 11.20$$

Question 7

Which of the following statements about strong acids is correct?

Accepted Answer

Their reaction equilibrium lies far to the right.

Question 8

What is the $$K_a of a $$weak acid if a 0.10 M solution has a pH of 2.8?

Accepted Answer

$$K_a = \frac{(1.6 	imes 10$$^{-3}$$)^2$$}{0.10 - 1.6 	imes $$10^{-3}$$} \approx 2.6 	imes $$10^{-5}$

Question 9

Which of the following is an example of a Lewis acid?

Accepted Answer

BF$$_3$$

Question 10

Which of the following best explains why HF is a weak acid, while HCl is a strong acid?

Accepted Answer

HF has a stronger H–F bond, making it harder to ionize.

Question 11

A solution has $$[OH^-] = 2.3 	imes 10$$^{-3}$$ M. What is the pH?

Accepted Answer

$$	ext{pOH} = -\log(2.3 	imes 10$$^{-3}$$) = 2.64$$, $$	ext{pH} = 14 - 2.64 = 11.36$$

Question 12

Which of the following statements about the autoionization of water is correct?

Accepted Answer

$$K_w = [H^+][OH^-] = 1.0 	imes 10$$^{-14}$$ at 25$$^\circ$$C

Question 13

Which of the following is a correct net ionic equation for the neutralization of HCl with NaOH?

Accepted Answer

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

Question 14

Which of the following best describes the relationship between $$K_a$$ and $$K_b$$ for a conjugate acid-base pair?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 15

A 0.10 M solution of acetic acid ($$K_a = 1.8 	imes 10$$^{-5}$$) is prepared. What is the approximate pH?

Accepted Answer

$$x = \sqrt{(1.8 	imes 10$$^{-5}$$)(0.10)} = 1.34 	imes 10$$^{-3}$$, $$	ext{pH} = -\log(1.34 	imes $$10^{-3}) = 2.87$

Question 16

Which of the following best explains why NaCl is a neutral salt in water?

Accepted Answer

Both Na$$^+$$ and Cl$$^-$$ are the conjugates of strong acid/base and do not hydrolyze water.

Question 17

Which of the following is true for a polyprotic acid such as H$$_2SO$_4$$?

Accepted Answer

The first ionization constant $$K_{a1} is $$much larger than the second $$K_{a2}.$$

Ch 16: Acid-Base Equilibria: Models, Strengths, and Electrolytes

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