Deck 16: Acids and Bases

Question 1

A solution with a pH of 2.17 is

A) basic
B) acidic
C) neutral

Answer 1

acidic

Question 2

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

A) HNO₃^-, H₂NO₃
B) HNH₄, NH₄⁺
C) H₂F, HF^-
D) HPO₄^2-, PO₄^3-
E) H₂CN, CN^-

Answer 2

HPO₄^2-, PO₄^3-

Question 3

Which of the following is the strongest conjugate acid?

A) HF
B)
C) HOCl
D) HCN
E) all the same

Answer 3

HF

Question 4

A solution where [H⁺] = 10^-13 M is ______________.

A) basic
B) neutral
C) acidic
D) strongly acidic
E) two of these

Question 5

Which of the following is not a conjugate acid-base pair?

A) H₂SO₄, SO₄^2-
B) HNO₃, NO₃^-
C) HC₂H₃O₂, C₂H₃O₂^-
D) H₂PO₄^-, HPO₄^2-
E) HBr, Br^-

Question 6

Consider the reaction HC₂H₃O₂(aq) + H₂O(l) $\rightarrow$ H₃O⁺(aq) + C₂H₃O₂^-(aq). Which species is the conjugate acid?

A) HC₂H₃O₂(aq)
B) H₂O(l)
C) H₃O⁺(aq)
D)
E) two of these

Question 7

Which of the following statements is/are correct?

A) In an acidic solution, [H⁺] > [OH^-].
B) In a basic solution, [OH^-] > [H⁺].
C) In a neutral solution, [H⁺] = [OH^-].
D) None of the above statements (a-c) are correct.
E) All of the above statements (a-c) are correct.

Question 8

Identify the Bronsted acids and bases in the following equation (A = Bronsted acid, B = Bronsted base): HSO₃^- + CN^- $\rightarrow$ HCN + SO₃^2-

A) B A B A
B) B B A A
C) A B A B
D) A B B A
E) B A A B

Question 9

A solution has [H⁺] = 4.0 *10^-3 M. The [OH^-] in this solution is

A) M
B) M
C) M
D) M
E) none of these

Question 10

A solution has [OH^-] = 3.0 *10^-7 M. The [H⁺] in this solution is

A) 1.0 M
B) M
C) M
D) M
E) none of these

Question 11

Calculate the [H⁺] in a solution that has a pH of 8.82.

A) M
B) M
C) M
D) M
E) none of these

Question 12

The conjugate acid of a weak base is a strong acid.

Question 13

A strong acid is one for which the forward reaction predominates.

Question 14

Arrhenius postulated that acids produce hydrogen ions in aqueous solution, whereas bases produce hydroxide ions.

Question 15

Choose the case that is not a Bronsted conjugate acid-base pair.

A) CH₃NH₃⁺, CH₃NH₂
B) HCN, CN^-
C) HClO₂, ClO₂^-
D) HCO₂H, HCOH
E) H₃BO₃, H₂BO₃^-

Question 16

Choose the pair of concentrations that cannot be in a given aqueous solution at 25°C.

A) [H⁺] = 10^-3 M, [OH^-] = 10^-11 M
B) [H⁺] = 10^-7 M, [OH^-] = 10^-7 M
C) [H⁺] = 10^-13 M, [OH^-] = 1 M
D) [H⁺] = 10 M, [OH^-] = 10^-15 M
E) All of these can exist.

Question 17

A solution is buffered by the presence of a weak acid and its conjugate base.

Question 18

Which of the following is the strongest conjugate base?

A) F^-
B) NH₃
C) OCl^-
D) CN^-
E) all the same

Question 19

Which has the higher [H⁺], 0.40 M RbOH or 0.20 M Ca(OH)₂?

A) Neither, the [H⁺]'s are equal.
B) 0.40 M RbOH
C) 0.20 M Ca(OH)₂
D) Neither, these are bases so there is no [H⁺].
E) The answer depends on the volumes of the respective solutions.

Question 20

As water is heated, its [H⁺] increases. This means that

A) the water is no longer neutral
B) [H⁺] > [OH^-]
C) [OH^-] > [H⁺]
D) a and b are correct
E) none of these

Question 21

What is the pH of a solution prepared by dissolving 96.1 g NaOH in enough water to make 3.2 L of solution?

A) 13.88
B) 0.12
C) 14.12
D) 10.28
E) none of these

Question 22

The pH of a solution at 25^oC in which [OH^-] = 3.5 *10^-5 M is

A) 4.46
B) 4.77
C) 9.54
D) 11.04
E) none of these

Question 23

How many moles of pure NaOH must be used to prepare 1.0 L of a solution that has pH = 12.26?

A) 8.2 * 10^-16 mol
B) 0.018 mol
C) 5.5 * 10^-13 mol
D) 1.74 mol
E) none of these

Question 24

Calculate the [H⁺] in a solution that has a pH of 5.15.

A) M
B) M
C) 8.85 M
D) 5.15 M
E) none of these

Question 25

Calculate the [OH^-] in a solution that has a pH of 3.76.

A) M
B) M
C) M
D) M
E) none of these

Question 26

A solution has [H⁺] = 5.0 *10^-8 M. The pH of this solution is

A) 6.70
B) 5.98
C) 7.30
D) 9.77
E) none of these

Question 27

A solution has [H⁺] = 4.3 *10^-8 M. The pOH of this solution is

A) 7.37
B) 6.63
C) 9.37
D) 3.28
E) none of these

Question 28

A solution is prepared by dissolving 111.9 g HCl(g) in enough water to make 160.0 L of solution. The pH of this solution is

A) 1.72
B) 12.28
C) 0.155
D) 3.07
E) none of these

Question 29

A solution has [OH^-]= 5.0 *10^-4 M. The pH of this solution is

A) 3.30
B) 2.00 * 10^-11
C) 5.35
D) 10.70
E) none of these

Question 30

What is the pH of a solution that has [OH^-] = .

A) 4.93 M
B) 9.07 M
C) 2.46 M
D) 7.14 M
E) none of these

Question 31

Which statement is true for a strong base solution with a concentration greater than 1.0 M?

A) pOH > pH
B) pH > pOH
C) pH < 0
D) pH<14
E) Two of these (a-d) are true.

Question 32

Calculate the [H⁺] in a solution that has a pH of 9.16.

A) M
B) M
C) 4.84 M
D) 9.16 M
E) none of these

Question 33

Calculate the [H⁺] in a solution that has a pH of 5.54.

A) 8.46
B) M
C) 5.54
D) M
E) none of these

Question 34

Solid calcium hydroxide is dissolved in water until the pH of the solution is 10.39. The hydroxide ion concentration [OH^-] of the solution is

A) M
B) 3.61 M
C) M
D) M
E) none of these

Question 35

A solution has a pH of 4.42. The [H⁺] in this solution is

A) 2.6 * 10^-10 M
B) 3.8 * 10^-5 M
C) 9.58
D) 4.42
E) none of these

Question 36

A solution with a pH of 2 is how many times more acidic as a solution with a pH of 6?

A) 3
B) 0.3
C) 100000
D) 10000
E) 8

Question 37

A solution has a pH of 3.16. The pOH of this solution is

A) 3.26
B) 10.74
C) 3.16
D) 10.84
E) none of these

Question 38

A solution with a pH of 3 is how many times as acidic as a solution with a pH of 5? (Ignore significant figures for this problem.)

A) 0.6 times as acidic
B) 2 times as acidic
C) 100 times as acidic
D) 15 times as acidic
E) 8 times as acidic

Question 39

Calculate the pH of a 0.045 M HCl solution.

A) 1.23
B) 1.35
C) 12.65
D) 12.29
E) none of these

Question 40

Calculate the pH of an acid solution containing 0.044 M HNO₃.

A) 12.64
B) 2.81
C) 1.36
D) 0.044
E) none of these

Question 41

Calculate the pH of M HCl.

A) 4.41
B) 9.59
C) 13.75
D) 6.90
E) none of these

Question 42

Calculate the pH of 0.056 M HClO₄.

A) 0.056
B) 7.00
C) 1.25
D) 12.75
E) none of these

Question 43

A weak acid, HOCl, is in solution with dissolved sodium hypochlorite, NaOCl. If HCl is added which ion will react with the extra hydrogen ions from the HCl to keep the pH from changing?

A) OCl^-
B) Na⁺
C) HOCl^-
D) OH^-
E) none of these

Question 44

A buffered solution contains HNO₂. It also contains

A) KCl
B) HNO₃
C) KOH
D) KNO₂
E) NaCl

Question 45

What is the pH of a 4.9 M solution of HClO₄?

A) 14.69
B) 0.69
C) -0.69
D) 13.31
E) minus infinity

Question 46

What is the pH of a 2.1 M solution of HNO₃?

A) -0.32
B) 0.32
C) 14.32
D) 13.68
E) none of these

Question 47

What is the pH of a 0.25 M nitric acid (HNO₃) solution?

A) 0.60
B) 2.50
C) 2.49
D) 13.40
E) none of these

Question 48

Which of the following is true for a buffered solution?

A) The solution resists any change in its [H⁺].
B) The solution will not change its pH very much even if a concentrated acid is added.
C) The solution will not change its pH very much even if a strong base is added.
D) Any H⁺ ions added will react with a conjugate base of a weak acid already in solution.
E) all of these

Question 49

A NaCl(aq) solution is automatically buffered.