Chemical Engineering Chapter 14 A metal and a salt solution will react only if

Introduction to Chemical Principles, 11e (Stoker)

Chapter 14 Acids, Bases and Salts

14.1 Multiple Choice

1) In an Arrhenius acid-base context, the compounds KOH, H2SO4, and HNO3 when dissolved

in water, function respectively as a(n) ________.

A) base, acid and acid

B) acid, base and base

C) base, acid and base

D) base, base and acid

2) Each of the following can act like a Bronsted-Lowry acid and Bronsted-Lowry base except:

A) NH4+

B) H2PO4–

C) HCO3–

D) HS–

3) A Bronsted-Lowry acid is defined as a substance that ________.

A) increases the [H+] concentration when placed in water

B) decreases the [H+] concentration when placed in water

C) acts as a proton donor in any system

D) acts as a proton acceptor in any system

4) According to the Bronsted-Lowry theory, a base is ________.

A) a hydronium ion donor

B) a proton donor

C) a proton acceptor

D) a hydroxide ion acceptor

5) Which of the following could not be a Bronsted-Lowry acid?

A) HF

B) HC2H3O2

C) CN−

D) HS−

6) The Bronsted-Lowry acid and base for the reaction

NH4+ + CN− —> NH3 + HCN are, respectively, ________.

A) NH3 and CN−

B) NH4+ and HCN

C) CN− and HCN

D) NH4+ and CN−

7) Which of the following is incorrectly classified as an acid, a base, a salt, or an amphoteric

species?

A) H2S acid

B) NH4+ base

C) LiOH base

D) HS− amphoteric

8) Which of the following is not a conjugate acid/base pair?

A) PH4+/PH3

B) H2O/OH−

C) HSO4−/SO42−

D) S2−/H2S

9) From the choices below, identify a conjugate acid-base pair. (The acid is listed first in the

pair.)

H2PO4− + S2− —> HS− + HPO42−

Acid Conjugate Base

A) S-2 HS–

B) H2PO4– S-2

C) H2PO4– HPO4-2

D) HS– H2PO4–

10) Which of the following pairs of acids and conjugate bases is incorrectly labeled?

Acid Conjugate Base

A) HSO4– SO4-2

B) HFO2 HFO3

C) HSO3– SO3-2

D) NH4+ NH3

11) Which of the following doesn’t represent a conjugate acid/base pair?

A) H3O+/H2O

B) HCN/CN–

C) HCl/Cl–

D) HC2H3O2/OH–

12) In which of the following pairs of acids are both chemical species of the pair polyprotic?

A) H2S and H2CO3

B) H3PO4 and HCN

C) HC2H3O2 and H3C6H5O7

D) HNO3 and H2C4H4O6

13) Which of the following is a species formed in the second step of the dissociation of H3PO4?

A) H2PO4−

B) HPO42−

C) PO43−

D) H3PO3

14) Which of the following is a triprotic acid?

A) HC2H3O2

B) H2SO3

C) H3PO4

D) HNO3

15) Which of the following is a diprotic acid?

A) HNO3

B) H2SO3

C) HCl

D) H3PO4

16) In which of the following pairs of acids are both chemical species in the pair weak acids?

A) H3PO4 and H2SO4

B) HCN and H2S

C) H2CO3 and HBr

D) HC2H3O2 and HI

17) Which of the following statements about weak acids is correct?

A) Weak acids always contain carbon atoms.

B) The percentage dissociation for weak acids is usually in the range of 40-60%.

C) Weak acids can only be prepared as dilute solutions.

D) Weak acid molecules have a strong affinity for acidic hydrogens.

18) Which of the following pairs is incorrectly matched?

Compound Classification

A) HI Strong acid

B) NH3 weak base

C) LiC2H3O2 salt

D) Ca(OH)2 weak base

19) Which of the following is not a strong acid?

A) H2CO3

B) H2SO4

C) HBr (aq)

D) HNO3

20) Which of the following is not a strong base?

A) NaOH

B) KOH

C) Fe(OH)3

D) Ca(OH)2

21) Which of the following is incorrectly classified as an acid, a base, a salt, or an amphoteric

species?

A) HCO3− amphoteric

B) NH3 base

C) KF salt

D) S2− amphoteric

22) The hydrogen sulfate ion HSO4– is amphoteric. In which of the following equations does it

act as an acid?

A) HSO4– + H2O —> H2SO4 + OH–

B) HSO4– + H3O+ —> SO3 + 2H2O

C) HSO4– + H2O —> SO4-2 + H3O+

D) HSO4– + OH– —> H2SO4 + O-2

23) In which of the following pairs of substances are both species in the pair salts?

A) LiOH and K2CO3

B) NaOH and HNO3

C) NH4F and KCl

D) CaCl2 and HCN

24) Complete the following acid-base reaction. What is the sum of the coefficients for the

balanced molecular equation LiOH (aq) + H2SO4 (aq) —>

A) 6

B) 9

C) 12

D) 14

25) Complete the following acid-base reaction. What is the sum of the coefficients for the

balanced molecular equation?BaCO3(aq) + HNO3(aq) —>

A) 8

B) 6

C) 9

D) 10

26) Which of the following statements about the reaction of acids with metals is incorrect?

A) Acids react with many, but not all, metals.

B) Any metal below hydrogen in the activity series will dissolve in a non-oxidizing acid.

C) Hydrogen gas is produced when a metal dissolves in acid.

D) Metal atoms which dissolve in acid become positive metal ions.

27) The neutralization of Cr(OH)3 with H2SO4 produces which of the following products?

A) OH−

B) H3O+

C) Cr2(SO4)3

D) SO2

28) A metal and a salt solution will react only if the metal going into the solution is ________.

A) above hydrogen in the activity series

B) below hydrogen in the activity series

C) above the replaced metal in the activity series

D) below the replaced metal in the activity series

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29) In which of the following pairs of substances will the two members of the pair not react?

A) HF and LiOH

B) PbCl2 and H2SO4

C) Na3PO4 and HCl

D) KCl and NaI

30) Which of the following pairs of 0.1 M solutions will react to form a precipitate?

A) NiBr2 and AgNO3

B) K2SO4 and CsI

C) NaI and KBr

D) KOH and Ba(NO3)2

31) An aqueous solution of sodium chloride will react with which of the following salts?

A) calcium nitrate

B) potassium bromide

C) lead(II) nitrate

D) barium nitrate

32) The product of [H3O+] and [OH−] in pure water, at 25 oC, is ________.

A) zero

B) always greater than 1

C) 1.00 x 10−7

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33) Which of the following solutions is acidic?

A) [H3O+] = 1.00 x 10−3

B) [H3O+] = 1.00 x 10−11

C) [H3O+] = 1.00 x 10−9

D) [H3O+] = 1.00 x 10−8

34) A solution with [H3O+] = 1.00 x 10−5 would have [OH−] equal to ________.

A) 1.00 x 10−5

B) 1.00 x 10−7

C) 1.00 x 10−9

D) 1.00 x 10−14

35) The pH of a solution for which [OH−] = 1.0 x 10−9 is ________.

A) 1.00

B) 5.00

C) 9.00

D) 1.00 x 10−5

36) The pH of a solution for which [H3O+] = 8.3 x 10−9 is ________.

A) 5.92

B) 9.60

C) 8.08

D) 6.00

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37) What is the pH of a solution that has a hydronium ion concentration of 3.98 x 10-9 M?

A) 5.600

B) 8.400

C) 9.000

D) 3.980

38) The [OH–] and the pH of 0.035 M KOH at 25 °C are, respectively, ________.

A) 0.035 M and +1.46

B) 0.035 M and -1.46

C) 2.9 x 10-13 M and -12.5

D) 0.035 M and +12.5

39) A solution with a pH of 2.1 is ________.

A) strongly acidic

B) weakly acidic

C) weakly basic

D) strongly basic

40) If the pH of a solution has decreased from 5.0 to 4.0 the [H3O+] ________.

A) increases by a factor of 1

B) increases by a factor of 10

C) decreases by a factor of 1

D) decreases by a factor of 10

41) In a solution with a pH of 9.64 the molar concentration of the hydrogen ion would be

________.

A) 1.4 x 10−9

B) 5.6 x 10−10

C) 2.3 x 10−11

D) 2.3 x 10−10

42) Which of the following does not describe an acidic solution?

A) The pH is less than 7.

B) The [OH−] is 1 x 10−4 M.

C) The [OH−] is less than the [H3O+].

D) The [OH−] is 6.0 x 10−10.

43) A solution has a pH = 6. What is the pH of a solution that is 1000 times less acidic?

A) 3

B) 7

C) 5

D) 9

44) Which of the following substances is most acidic?

A) soap, pH 9.0

B) a tomato, [OH−] = 2.5 10-10

C) rain water, [H+] = 2.0 10−6

D) liquid bleach, [OH−] = 1.0 10−2

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45) A solution has a pH of 3.0. What is the pH of a solution that is 100 times more basic?

A) 1.0

B) 3.0

C) 5.0

D) 13.0

46) The pH of a solution is 5.46. Determine the [H3O+] for the solution.

A) 1.9 x 10−5

B) 3.5 x 10−6

C) 5.6 x 10−4

D) 1.1 x 10−6

47) The pH of a solution is 8.11. Determine the [H3O+] for the solution.

A) 7.8 x 10-9 M

B) 1.3 x 108 M

C) 1.3 x 10-8 M

D) 8.1 x 10-8 M

48) The pH of a solution is 3.75. Determine the [H3O+] for the solution.

A) 5.6 x 103 M

B) 7.5 x 10-3 M

C) 5.6 x 10-11 M

D) 1.8 x 10-4 M

49) Which one of the following salts will hydrolyze to give an acidic solution?

A) NH4Cl

B) LiNO3

C) KC2H3O2

D) Na2S

50) Which of the following compounds will not hydrolyze?

A) HF

B) H2S

C) NaC2H3O2

D) HCl

51) If the pH of a solution of a salt is 10.5, the salt must be one which could be formed from the

neutralization of ________.

A) a strong acid and a strong base

B) a weak acid and a strong base

C) a strong acid and a weak base

D) HCl and NaOH

52) Which of the following salts will hydrolyze to give an acidic solution?

A) LiNO3

B) NaCl

C) CH3NH3+

D) NaC2H3O2

53) Which is the correct net ionic equation for the hydrolysis reaction of Na2S?

A) S2− (aq) + H2O (l) —>HS− (aq) + OH− (aq)

B) S2− (aq) + 2 H2O (l) —> HS− (aq) + H3O+ (aq)

C) Na+ (aq) + H2O (l) —> NaOH (aq) + H2 (g)

D) Na+ (aq) + 2 H2O (l) —> NaOH (aq) + H2O+ (aq)

54) An aqueous solution of which of these salts will be basic?

A) NH4ClO4

B) KBr

C) CrCl3

D) NaF

55) Which of the following pairs of substances could not function as a buffer system in aqueous

solution?

A) HClO4 and KClO4

B) HNO2 and NaNO2

C) NaHCO3 and Na2CO3

D) HF and LiF

56) Which of the following pairs of substances could not function as a buffer system in aqueous

solution?

A) KC2H3O2 and HC2H3O2

B) KHSO3 and H2SO3

C) HCl and NaCl

D) K2HPO4 and NaH2PO4

57) Which of the following substances, when added to a solution of nitrous acid (HNO2) could

be used to prepare a buffer solution?

A) HCl

B) NaCl

C) HC2H3O2

D) NaNO2

58) How many grams of tartaric acid, H2C4H4O6, (molar mass = 150.10 g) are needed to

produce 50.0 mL of 0.360 M H2C4H4O6 solution?

A) 1.36 g

B) 5.62 g

C) 11.2 g

D) 2.70 g

59) If 12.3 mL of 0.25 M HNO3 is required to titrate 18.4 mL of Ba(OH)2, the molarity of the

Ba (OH)2 solution is ________.

A) 0.012 M

B) 0.80 M

C) 0.084 M

D) 2.4 M

60) How many mL of a 0.100 M NaOH solution is needed to neutralize 50.00 mL of a 0.150 M

solution of HC2H3O2?

A) 25.0 mL

B) 37.5 mL

C) 75.0 mL

D) 100. mL

61) In a titration 35.84 mL of 0.2419 M HCl solution is required to completely neutralize 18.62

mL of Fe(OH)3 solution. What is the molarity of the Fe(OH)3 solution?

3 HCl + Fe(OH)3 —> FeCl3 + 3 H2O

A) 0.1552 M

B) 0.4656 M

C) 0.1164 M

D) 0.3492 M

62) Titration of 37.22 mL of Ca(OH)2 solution requires 31.19 mL of 0.219 M H3PO4 solution

according to the following equation:

3 Ca(OH)2 (aq) + 2 H3PO4 (aq) —> Ca3(PO4)2 (s) + 6 H2O (l)

What is the molarity of the base in this reaction?

A) 0.275 M

B) 0.122 M

C) 0.184 M

D) 0.392 M

63) If 30.0 mL of 0.40 M H2SO4 is required to neutralize 15.0 mL of NaOH, the molarity of the

NaOH solution is ________. H2SO4 (aq) + 2 NaOH (aq) —> Na2SO4 (aq) + 2 H2O (l)

A) 1.6 M

B) 0.40 M

C) 0.80 M

D) 2.4 M

64) What is the concentration of a nitric acid solution if a 10.00 mL sample of the acid requires

31.25 mL of a 0.135 M KOH to neutralize it?

A) 0.0432 M

B) 0.422 M

C) 0.844 M

D) 0.135 M

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14.2 Short Answer

1) Identify the acid (A), base (B), conjugate acid (CA) and conjugate base (CB) in each of the

following reactions:

A) HSO4–(aq) + ClO–(aq) —> HClO (aq) + SO4-2 (aq)

B) H2C2O4 (aq) + NH3 (aq) —> HC2O4– (aq) + NH4+

2) Consider the following reaction:

H2SO3 + HCO3– —> H2CO3 + HSO3–

A) Identify the acid, base, conjugate acid and conjugate base

B) Identify two substances from the reaction which could be used to prepare a buffer.

3) Write an equation for the response of a HCO3−/CO32− buffer to the addition of OH− ions.

4) Write an equation for the response of a HF/F− buffer to the addition of H3O+ ions.