Q: A 0.10 M solution of acetic acid ($$\mathrm{CH_3COOH}$$, $$K_a = 1.8 \times 10$$^{-5}$$) has a measured $$[H^+]$$ of 1.34$$ \times $$10^{-3} M. $$What is the percent dissociation of acetic acid in this solution?

$$\frac{1.34 \times 10$$^{-3}$$}{0.10} \times 100 = 1.34\%$$

Question 1

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

Accepted Answer

A substance that donates a proton (H+)

Question 2

A 0.10 M solution of acetic acid ($$\mathrm{CH_3COOH}$$, $$K_a = 1.8 	imes 10$$^{-5}$$) has a measured $$[H^+]$$ of 1.34$$ 	imes $$10^{-3} M. $$What is the percent dissociation of acetic acid in this solution?

Accepted Answer

$$\frac{1.34 	imes 10$$^{-3}$$}{0.10} 	imes 100 = 1.34\%$$

Question 3

Which of the following household items is most likely to have a pH greater than 7?

Accepted Answer

Baking soda

Question 4

What is the pH of a 0.10 M solution of HCl, a strong acid?

Accepted Answer

$$pH = -\log(0.10) = 1.0$$

Question 5

Which of the following statements about the relationship between $$K_a$$ and acid strength is correct?

Accepted Answer

A larger $$K_a$$ value means a stronger acid

Question 6

If the $$K_w$$ for water at 25°C is $$1.0 	imes 10$$^{-14}$$, what is the relationship between pH$ and $$pOH$$?

Accepted Answer

$$pH + pOH = 14$$

Question 7

A 0.1 M solution of NaCl is prepared. Which statement best describes the pH of this solution?

Accepted Answer

The solution is neutral because both Na+ and Cl- are spectator ions

Question 8

Which equation correctly expresses the relationship between $$K_a$$, $$K_b$$, and $$K_w$$ for a conjugate acid-base pair?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 9

Which of the following 0.1 M solutions will have the highest pH?

Accepted Answer

KCN

Question 10

What is the $$[OH^-] in a 0.1 M $$NaOH solution?

Accepted Answer

$$[OH^-] = 0.1 M$

Question 11

A solution has a pH of 10.5. What is the $$[H^+]$$ concentration?

Accepted Answer

$$[H^+] = 10$$^{-10.5}$$ M$

Question 12

Which of the following is a polyprotic acid?

Accepted Answer

H2SO4

Question 13

What is the pH of a 1.0 x $$10^{-4} M $$HCl solution, considering the contribution of water?

Accepted Answer

$$pH = 4$$

Question 14

Which of the following reactions represents the auto-ionization of water?

Accepted Answer

$$H_2O + H_2O \rightleftharpoons H_3O^+ + OH^-$$

Question 15

Which of the following best describes the effect of adding acid to a solution containing $$CaCO_3$$?

Accepted Answer

The $$CaCO_3$$ dissolves more

Question 16

Which of the following is the correct equilibrium constant expression for the dissociation of a weak acid $$HA$$?

Accepted Answer

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

Question 17

Which of the following is a Lewis base?

Accepted Answer

A substance that donates a lone pair of electrons

Question 18

Which of the following best explains why a 0.1 M NH4Cl solution is acidic?

Accepted Answer

NH4+ acts as a weak acid and donates H+ to water

Question 19

Which formula is used to calculate the pH of a solution?

Accepted Answer

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

Chapter 17: Acids and Bases – General Chemistry Study Notes

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