Acids Quiz #4 Anhydrides, Hydrolysis Answers

1. Which of the following pairs of gases are primarily responsible for producing

“acid rain”?

A. O₂ and O₃

B. N₂ and O₂

C. CO and CO₂

D. NO₂ and SO₂

2. Sodium potassium tartrate (NaKC₄H₄O₆) is used to raise the pH of fruit during

processing. In this process, sodium potassium tartrate is being used as a/an

A. salt

B. acid

C. base

D. buffer

3. The net ionic equation for the hydrolysis of the salt, Na₂S is

A. Na₂S ⇄ 2Na⁺ + S^2-

B. S^2- + H₂O ⇄ OH^- + HS⁺

C. Na₂S + 2H₂O ⇄ 2NaOH + H₂S

D. 2Na⁺ + S^2- + 2H₂O ⇄ 2Na⁺ + 2OH^- + H₂S

4. Which of the following solutions would be acidic?

A. sodium acetate

B. iron III chloride

C. sodium carbonate

D. potassium chloride

5. Consider the following salts:

I. NaF II. NaClO₄ III. NaHSO₄

Which of these salts, when dissolved in water, would form a basic solution?

A. I only

B. I and II only

C. II and III only

D. I, II and III

6. Which of the following, when dissolved in water, forms a basic solution?

A. KCl

B. NaClO₄

C. Na₂CO₃

D. NH₄NO₃

7. Which of the following oxides forms a basic solution?

A. K₂O

B. CO₂

C. SO₃

D. NO₂

8. Which of the following is amphiprotic in water?

A. SO₂

B. SO₃^2-

C. HSO₃^-

D. H₂SO₃

9. Consider the following equilibrium expression

K= [H₂S][ OH ^- ]

[HS^-]

This expression represents the

A. K_b for H₂S

B. K_a for H₂S

C. K_b for HS^-

D. K_a for HS^-

10. The reaction of a strong acid with a strong base produces

A. A salt and a water

B. A base and an acid

C. A metallic oxide and water

D. A non-metallic oxide and water

11. Consider the following equilibrium:

CH₃COOH_(aq) + NH_3(aq) ⇄ CH₃COOH^-_(aq) ⇄ NH₄⁺_(aq)

The sequence of Bronsted-Lowry acids and bases is

A. acid, base, base, acid

B. acid, base, acid, base

C. base, acid, base, acid

D. base, acid, acid, base

12. The pH range of ‘acid rain’ is often

A. 3 to 6

B. 6 to 8

C. 7 to 9

D. 10 to 12

13. Water will act as a Bronsted-Lowry acid with

A. NH₃

B. H₂S

C. HCN

D. HNO₃

14. Which of the following is a conjugate acid-base pair?

A. H₃PO₄ and PO₄^3-

B. H₂PO₄^- and PO₄^3-

C. H₃PO₄ and HPO₄^2-

D. H₂PO₄^- and HPO₄^2-

15. What is the net ionic equation for the hydrolysis of NH₄Cl ?

A. NH₄Cl ® NH₄⁺ + Cl^-

B. Cl^- + H₂O ⇌ HCl + OH^-

C. NH₄⁺ + H₂O ⇌ H₃O⁺ + NH₃

D. NH₄⁺ + H₂O ⇌ NH₅⁺ + OH^-

16. What is the approximate pH of the salt NH₄Cl?

A. 0.0

B. 5.0

C. 7.0

D. 9.0

17. Four samples of rain are collected from different geographic regions and the pH is

measured for each sample.

Sample pH

1 2.8

2 4.0

3 6.2

4 6.8

Which of the above samples would be classified as acid rain?

A. 1 only

B. 1 and 2

C. 1, 2 and 3

D. 1, 2, 3 and 4

18. Which of the following equations correctly represents the reaction of a metallic

oxide with water?

A. K₂O + H₂O ® 2KOH

B. SO₃ + H₂O ® H₂SO₄

C. Na₂O + H₂O ® Na₂O₂ + H₂

D. NaOH + HCl ® NaCl + HOH

19. Which of the following equations describes the dissociation of the salt,

ammonium chloride, in water?

A. NH₄Cl_(s) ® NH₄Cl_(aq)

B. NH₄⁺_(aq) + Cl^-_(aq) ® NH₄Cl_(s)

C. NH₄Cl_(s) ® NH₄⁺_(aq) + Cl^-_(aq)

D. NH₄⁺_(aq) + H₂O_(l) ® H₃O⁺_(aq) + NH_3(aq)

20. Which of the following salt solutions is acidic?

A. NaBr

B. AlCl₃

C. Li₂CO₃

D. NaHCO₃

21. What pH would most likely result when CO₂ dissolves naturally in rainwater?

A. 3.0

B. 6.6

C. 7.0

D. 7.5

22. Which of the following is the net ionic equation that describes the hydrolysis that

occurs in a K₂CO₃ solution?

A. K₂CO₃ ® 2K⁺ + CO₃^2-

B. 2K⁺ + CO₃^2- ® K₂CO₃

C. CO₃^2- + H₂O ® HCO₃^- + OH^-

D. K₂CO₃ + 2H₂O ® H₂CO₃ + 2KOH

23. What is the equilibrium expression for the predominant equilibrium in

NaCN_(aq)?

A. Kb = [Na⁺][CN^-]

[NaCN]

B. Kb = [Na⁺][CN^-]

[HCN]

C. Kb = [HCN][OH^-]

[CN^-]

D. Kb = [CN^-][OH^-]

[HCN]

24. Which of the following salts will be basic?

A. KCl

B. NH₄Cl

C. NaBr

D. Na₂HPO₄

25. Which of the following salts will be acidic?

A. KCl

B. NH₄Cl

C. NaBr

D. Na₂HPO₄

26. Which is an acid anhydride?

A. Na₂O

B. NaCl

C. CO₂

D. NH₄Cl

27. Which formula has the highest pH when in water?

A. Na₂O

B. NaCl

C. CO₂

D. NH₄Cl

28. Which formula has the lowest pH when in water?

A. Na₂O

B. NaCl

C. FeCl₃

D. NaHCO₃

29. Which formula has the lowest pH when in water?

A. NaCN

B. Na₂HPO₄

C. NH₄Cl

D. NaOH

30. Which of the following properties is true for a solution of NaNO₃ ?

A. It is neutral.

B. It is very basic.

C. It is slightly basic.

D. It is slightly acidic.