Deck 11: Acids and Bases

Question 1

Which of the following compounds is not an Arrhenius acid?

A) HCl
B) H₂SO₄
C) H₂O
D) FeCl₃
E) H₂S

Answer 1

FeCl₃

Question 2

Which of the following compounds is not an Arrhenius base?

A) NaOH
B) Al(OH)₃
C) Ca(OH)₂
D) H₂O
E) NH₃

Answer 2

NH₃

Question 3

Consider the following reaction:
H₂PO₄^-(aq) + HCO₃^-(aq) H₂CO₃(aq) + HPO₄^2-(aq)
Brønsted would identify the acidic species as:

A) H₂PO₄^- and H₂CO₃
B) H₂PO₄^- and HPO₄^2-
C) HCO₃^- and H₂CO₃
D) HCO₃^- and HPO₄^2-
E) H₂CO₃ and HPO₄^2-

Answer 3

H₂PO₄^- and H₂CO₃

Question 4

Which compound cannot act as a Brønsted base?

A) NH₃
B) H₂O
C) CH₄
D) F^-
E) H₂S

Question 5

Which of the following compounds cannot be a base?

A) H₂O
B) NH₃
C) CO₃^2-
D) OH^-
E) NH₄⁺

Question 6

Which of the following isn't a Brønsted base?

A) PF₅
B) H₂O
C) NH₃
D) S^2-
E) CN^-

Question 7

What is the conjugate acid of hydrogen carbonate ion, HCO₃ ^- ?

A) H₃O⁺
B) OH ^-
C) H₂O
D) CO₃^{2 -}
E) H₂CO₃

Question 8

What is the conjugate base of thiocyanic acid, HSCN?

A) H₃O⁺
B) OH ^-
C) SCN ^-
D) CN ^-
E) H₂SCN⁺

Question 9

The dihydrogen phosphate ion, H₂PO₄ ^- , can behave as both an acid and as a base. What is the chemical formula of the conjugate acid of dihydrogen phosphate? What is the chemical formula of the conjugate base of dihydrogen phosphate?

A) conjugate acid = H₃PO₄ conjugate base = HPO₄^{2 -}
B) conjugate acid = H₂PO₄⁺ conjugate base = H₂PO₄^{2 -}
C) conjugate acid = HPO₄^{2 -} conjugate base = H₃PO₄
D) conjugate acid = H₃PO₄ conjugate base = PO₄^{3 -}
E) none of these

Question 10

Ethanol (CH₃CH₂OH), like water, can behave both as an acid or as a base. Which of the following structures corresponds to the Brønsted conjugate acid and conjugate base of ethanol?

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

Question 11

What is the conjugate base of HSO₄^-?

A) H₂O
B) H₂SO₄
C) HSO₄^-
D) SO₃
E) none of the above

Question 12

Methanol is described by the following skeleton structure.

Which substance is formed when CH₃OH acts as a Brønsted base?

A) CH₃O^-
B) CH₃OH
C) CH₃OH₂⁺
D) CH₃OH.
E) H₃O⁺

Question 13

The compound HB can be represented as where represent B^- and represents H⁺. Given this, ___ would represent the conjugate acid of HB and ____ would represent the conjugate base.

A) 1,2
B) 1,5
C) 3,4
D) 1,3
E) None of the above.

Question 14

Which of the following is the conjugate base of a strong acid?

A) OH^-
B) HSO₄^-
C) NH₂^-
D) S^2-
E) H₃O⁺

Question 15

Which of the following represents a conjugate acid/base pair?

A) H⁺, OH^-
B) H₃O⁺, OH^-
C) NH₃, NH₄⁺
D) NaOH, HCl
E) All of the above are conjugate acid/base pairs.

Question 16

A solution is known to have a hydronium ion concentration of 1.0 x 10^-6 M. What percentage of the total H₃O⁺ ion concentration comes from the dissociation of water?

A) 1%
B) 3%
C) 5%
D) 10%
E) 100%

Question 17

What is the [H₃O⁺] concentration of a solution with a pH of 8.75?

A) 1.8 x 10 ^{- 9}M
B) 9.4 x 10 ^{- 1}M
C) 8.7 x 10^-5M
D) 5.6 x 10⁸M
E) This is a basic solution, [H₃O⁺] cannot be determined.

Question 18

A solution of weak base is added to a beaker of water. Which of the following will be true as the base is added to the water?

A) [H₃O⁺] increases [OH ^- ] decreases pH increases
B) [H₃O⁺] decreases [OH ^-F ] increases pH decreases
C) [H₃O⁺] decreases [OH ^- ] decreases pH increases
D) [H₃O⁺] remains constant [OH ^- ] increases pH increases
E) none of these

Question 19

Determine the [OH ] for an aqueous solution at 25 C with a pH of 4.80.

A) 6.3x10 ¹⁰M
B) 1.6x10 ⁵M
C) 1.6x10 ⁹M
D) 8.0x10 ⁸M
E) none of these

Question 20

A strong acid is added to water. Which of the following will be true?

A) [H₃O⁺] increases, [OH ^- ] decreases, pH increases
B) [H₃O⁺] decreases, [OH ^- ] increases, pH decreases
C) [H₃O⁺] decreases, [OH ^- ] decreases, pH decreases
D) [H₃O⁺] increases, [OH ^- ] increases, pH increases
E) none of these

Question 21

What is the H₃O⁺ ion concentration in a solution that has a pH of 5.75?

A) 5.8 x 10^-5 M
B) 3.2 x 10^-3 M
C) 0.75 x 10^-5 M
D) 3.6 x 10^-7 M
E) 1.8 x 10^-6 M

Question 22

What is the pH of a solution that is 1.7 x 10^-4 M in H₃O⁺?

A) 3.77
B) 4.77
C) 4.23
D) 10.23
E) none of these

Question 23

What is the hydroxide ion concentration in a pH = 5.14 solution?

A) 1.0 x 10^-14
B) 1.4 x 10^-9
C) 1.0 x 10^-7
D) 7.2 x 10^-6
E) 1.4 x 10^-2

Question 24

Which equation best describes a 0.10 M solution of a strong acid such as hydroiodic acid (HI: K_a = 3 x 10⁹)?

A) [H₃O⁺] = initial concentration of HI
B) [H₃O⁺] $\approx$ [OH^-]
C) [H₃O⁺] $\approx$ final concentration of HI
D) [H₃O⁺] $\approx$ [H₂O]
E) [H₃O⁺] $\approx$ K_a.[OH^-]

Question 25

Which of the following acids would have the strongest conjugate base?

A) HOCl (K_a = 2.9 x 10^-8)
B) HOBr (K_a = 2.4 x 10^-9)
C) HOI (K_a = 2.3 x 10^-11)
D) H₂O₂ (K_a = 2.2 x 10^-12)
E) H₂O (K_a = 1.8 x 10^-16)

Question 26

Using a table of K_a's, determine which of the following is the strongest Brønsted acid.

A) NH₄⁺
B) HCl
C) HNO₃
D) HSO₄^-
E) HClO₄

Question 27

Using a table of K_a's, determine which of the following is the strongest base.

A) I^-
B) NO₃^-
C) HS^-
D) O^2-
E) OH^-

Question 28

Using a table of K_a's, determine which of the following is the strongest acid.

A) NH₂^-
B) HS^-
C) H₂O
D) CH₄
E) NH₄⁺

Question 29

If the strength of the following acids increases from left to right
CH₃NH₂ < CH₃NH₃⁺ < C₆H₅NH₃ ⁺ < C₆H₅CO₂H < HCl

The order of increasing base strength, reading from left to right, must be:

A) CH₃NH^- < CH₃NH₂ < C₆H₅NH₂ < C₆H₅CO₂^- < Cl^-
B) Cl^- < C₆H₅CO₂^- < C₆H₅NH₂ < CH₃NH₂ < CH₃NH^-
C) C₆H₅NH₂ < CH₃NH₂ < Cl^- < C₆H₅CO₂^- < CH₃NH^-
D) CH₃NH^- < C₆H₅CO₂^- < Cl^- < CH₃NH₂ < C₆H₅NH₂
E) none of the above

Question 30

Explain the following observation: Water becomes acidic when CO₂ is bubbled into it.

Question 31

Which of the following is the weakest acid?

A) HClO₄
B) HCl
C) HF
D) HI
E) HBr

Question 32

Arrange the following bases in order of increasing strength: NH₃, PH₃, H₂O and H₂S.

Question 33

Which of the following statements is true?

A) H₂O is a stronger acid than HF(aq).
B) H₂O is a stronger acid than H₂S(aq).
C) H₂O is a stronger acid than the H₃O⁺(aq) ion.
D) H₂O is a stronger acid than NH₃(aq).
E) None of the above are true.

Question 34

What can be correctly concluded from the fact that the following acid-base reaction proceeds to the right, as written?

NH₂^-(aq) + HSO₄^-(aq) NH₃(aq) ⁺ SO₄^2-(aq)

A) NH₃ is a stronger base than NH₂^-.
B) NH₃ is a stronger acid than HSO₄^-.
C) NH₃ is a weaker acid than NH₂^-.
D) NH₃ is a weaker base than HSO₄^-.
E) NH₃ is a weaker acid than HSO₄^-.

Question 35

Which of the following statements is true?

A) H₂O is a weaker acid than NH₃.
B) PH₃ is a weaker acid than NH₃.
C) OH^- is a weaker base than H₂O.
D) NH₂^- is the conjugate acid of NH₃.
E) ClO^- is a stronger base than ClO₄^-.

Question 36

The hydride ion, (H^-), is a stronger base than the hydroxide ion, (OH^-). The products of the reaction between H^- (aq) and H₂O(l) would be.

A) H₂O(aq)
B) OH^- (aq) + H₂(g)
C) OH^- (aq) + 2H⁺(aq)
D) H₂O₂(aq)
E) No reaction would occur.

Question 37

Which of the following structural factors is primarily responsible for H₂Se being a stronger acid than H₂S?

A) bond polarity
B) size of the anion
C) electron withdrawing effect of oxygen
D) electric charge on the acid
E) sulfur has d electrons

Question 38

Which of the following is the best Lewis structure for carbonic acid (H₂CO₃)?

A)
B)
C)
D)
E)

Question 39

Of the following, which is the strongest acid (lone pairs omitted for clarity)?

A)
B)
C)
D)

Question 40

Which of the following structural factors is primarily responsible for H₂AsO₄ ^- being a stronger acid than HAsO₄^{2 -} ?

A) bond polarity
B) size of the anion
C) electron withdrawing effect of oxygen
D) electric charge on the acid
E) arsenic has d electrons

Question 41

Which of the following would you expect to be the strongest acid?

A) NH₃
B) PH₃
C) H₂O
D) H₂S
E) CH₄

Question 42

Which of the following would be the weakest Brønsted acid?

A) H₂Se
B) H₂S
C) H₂O
D) SH^-
E) OH^-

Question 43

Which of the following would be the strongest Brønsted base?

A) HSO₃^-
B) HSO₄^-
C) H₂SO₃
D) SO₃^2-
E) SO₄^2-

Question 44

Which of the following would be the strongest Brønsted base?

A) H₂O
B) SH^-
C) OH^-
D) S^2-
E) O^2-

Question 45

What is the pOH of a 0.025M solution of hydrobromic acid (K_a = 1 x 10⁹)?

A) 0.025
B) 1.60
C) 12.40
D) 9.00
E) 5.00

Question 46

What is the pH of a 0.0250 M HClO₄ solution.

A) 2.50
B) -2.50
C) 1.60
D) 12.40
E) none of these

Question 47

Which of the following statements should be true for a 1.0x 10 ^{- 4} M solution of a strong acid HBr?

A) [Br ^- ] >> [H₃O⁺]
B) pH = 4.00
C) [HBr] = 1.0 x 10 ^{- 4}M
D) [Br ^- ] = [HBr]
E) pH = 1.00

Question 48

Which of the following statements is true for a 1.0 M solution of the strong acid HCl in water?

A) [Cl ^- ] > [H₃O⁺]
B) The pH is 1.00
C) [H₃O⁺] = 1.0 M
D) [HCl] = 1.0 M
E) [H₃O⁺] = [OH ^- ]

Question 49

Assume a solution is prepared by adding 1.0 x 10^-3 moles of a weak monoprotic acid (K_a = 2.0 x 10^-4) to enough water to give a liter of solution. If you want to compute the H₃O⁺ ion concentration with an error of 5% or less, you can legitimately ignore:

A) both the contribution of the dissociation of water and the $\Delta$ C term.
B) neither the dissociation of water nor the $\Delta$ C term.
C) the dissociation of water but not the $\Delta$ C term.
D) the $\Delta$ C term but not the dissociation of water.
E) You can't compute the H₃O⁺ concentration with an error of less than 5%.

Question 50

When 1.0 x 10^-5 mole of HOCl (K_a = 3.5 x 10^-8) is dissolved in pure water and diluted to 1.00 L, which assumption can't be applied in the calculation of the pH of this solution?

A) that the initial concentration of HOCl is much larger than the total H₃O⁺ ion concentration
B) that the H₃O⁺ ion concentration from the dissociation of water can be ignored.
C) that the total H₃O⁺ ion concentration is the sum of the concentrations from the dissociation of HOCl and water
D) all of these assumptions are valid
E) none of these assumptions are valid

Question 51

For a particular weak acid, HA, in pure water, as the initial concentration of the weak acid increases, the acid-dissociation equilibrium constant of that acid should

A) increase.
B) decrease.
C) remain the same.
D) increase until the ionization of water can be neglected.
E) decrease until the ionization of water can be neglected.

Question 52

What would happen if more formic acid (HCO₂H) was added to the following solution at equilibrium?
HCO₂H(aq) + H₂O(l) H₃O⁺(aq) + HCO₂^-(aq)

A) [H₂O] should increase.
B) [H₃O⁺] and [HCO₂^-] should both increase.
C) [H₃O⁺] and [HCO₂^-] should both decrease.
D) [H₃O⁺] should increase but [HCO₂^-] should decrease.
E) [H₃O⁺] should decrease but [HCO₂^-] should increase.

Question 53

Which of the following equations is valid for a 0.10 M solution of formic acid, HCO₂H?
HCO₂H(aq) + H₂O(l) HCO₂^-(aq) + H₃O⁺(aq)   K_a = 1.8 x 10^-4

A) [H₃O⁺] < [OH^-]
B) [H₃O⁺] = [HCO₂H]
C) [H₃O⁺] = [HCO₂^-]
D) [H₃O⁺] = [H₂O]
E) [OH^-] = [H₂O]

Question 54

Which of the following isn't true for the H₃O⁺ ion concentration in a
0)0100 M solution of acetic acid (K_a = 1.8 x 10^-5)?

A) It is less than the H₃O⁺ concentration in an 0.0100 M solution of HCl.
B) It is equal to the OAc^- ion concentration.
C) It is equal to the OH^- ion concentration.
D) The pH of the solution is less than 7.0.
E) None of the above are true.

Question 55

Calculate the approximate pH of a 0.10 M lactic acid solution.
(K_a = 8.4 x 10^-4)

A) 2.0
B) 3.0
C) 4.0
D) 7.0
E) 12.0

Question 56

Calculate the approximate pH of a 0.100 M solution of formic acid (HCO₂H) in water. (HCO₂H: K_a = 1.8 x 10^-4)

A) 2.4
B) 3.7
C) 4.7
D) 7
E) 11.6

Question 57

Hydrogen peroxide has been used as a bleach to change hair color, as a disinfectant to treat wounds and as a rocket fuel. It is also a weak acid. Calculate the pH of a 0.018 M H₂O₂ solution. (H₂O₂: K_a = 2.2 x 10^-12)

A) 0.6
B) 6.7
C) 7.3
D) 11.7
E) 13.4

Question 58

A 0.10 M solution of a weak acid, HA, is found to be 1.50% ionized. Calculate K_a for this acid.

A) 1.5
B) 2.3 x 10^-1
C) 2.3 x 10^-5
D) 2.3 x 10^-6
E) none of the above

Question 59

A solution is prepared by dissolving 1.0 x 10^-4 moles of HOBr in water and diluting to 1.00 L. What is the pH of this solution? (HOBr: K_a = 2 x 10^-9)

A) 1.3
B) 5.3
C) 6.3
D) 8.7
E) 12.7

Question 60

Which of the following groups contains salts that all form basic solutions in water?

A) NaNO₃, NH₄CN, NaOAc, NH₄Cl
B) Na₂CO₃, KCl, NaOAc, NH₄Cl
C) Na₂CO₃, NaF, NaOAc, NaCN
D) NaHCO₃, NaF, NH₄Cl, Na₂SO₃
E) none of the above

Question 61

Which of the following compounds aren't acids in water?

(I) NH₄Cl (II) HNO₃ (III) NH₃ (IV) HI (V) K₂S

A) I and II
B) II and III
C) III and V
D) I, II and IV
E) all of the above are acids in water

Question 62

K_b for methylamine (CH₃NH₂) is the equilibrium constant for which reaction?

A) CH₃NH₂ + H₂O CH₃NH^- + H₃O⁺
B) CH₃NH₂ + H₂O CH₃NH₃⁺ + OH^-
C) CH₃NH₂ + H₃O⁺ CH₃NH₃⁺ + H₂O
D) CH₃NH₂ + OH^- CH₃NH^- + H₂O
E) None of the above

Question 63

What is the K_b for methylamine (CH₃NH₂) if a 0.10 M solution of this weak base is 6.8% ionized?

A) 5.0 x 10^-4
B) 0.068
C) 4.6 x 10^-5
D) 2.0 x 10³
E) 1.0

Question 64

Which of the following won't produce an acidic solution when dissolved in water?

A) HF
B) NH₄Cl
C) CH₃CO₂H
D) CH₃CO₂Na
E) HClO₄

Question 65

Sodium fluoride, NaF (a soluble salt), is dissolved in water. Which one of the following correctly describes the relationships between the concentrations of the species present at equilibrium?

A) [ F^- ] < [HF] and [Na⁺] [ F^- ]
B) [F ^- ] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [Na⁺] and [H₃O⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [F ^- ]
C) [ F ^- ] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 0 [HF] and [Na⁺] < [ F ^- ]
D) [OH ^- ] < [HF] and [Na⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [ F ^- ]
E) none of these

Question 66

The salt NaF is dissolved in water. Which of the following relationships would be true for the species in solution?

A) [Na⁺] [F ^- ] >> [HF] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [H₃O⁺] >> [OH ^- ]
B) [Na⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [F ^- ] >> [HF] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OH ^- ] >> [H₃O⁺]
C) [Na⁺] >> [F ^- ] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [HF] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OH ^- ] >> [H₃O⁺]
D) [Na⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [HF] >> [F ^- ] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OH ^- ] >> [H₃O⁺]
E) none of these

Question 67

When NH₄Cl is dissolved in water the following species will be present: NH₄⁺, Cl ^- OH ^- , H₃O⁺, and NH₃. Which of the following represents the correct relationship between the species in solution?

A) [NH₄⁺] [Cl ^- ] > [OH ^- ] > [NH₃] > [H₃O⁺]
B) [NH₄⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [Cl ^- ] > [NH₃] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [H₃O⁺] > [OH ^- ]
C) [NH₄⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [Cl ^- ] > [NH₃] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OH ^- ] > [H₃O⁺]
D) [NH₃] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OH ^- ] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [Cl ^- ] > [NH₄⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [H₃O⁺]
E) [NH₃] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [H₃O⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [Cl ^- ] > [NH₄⁺] 11ee9f02_5f5c_eb1b_9fac_d5ba514ecb51_TB9692_11 [OHF ^- ]

Question 68

What is the value of K_b for the formate (HCO₂^-) ion if K_a for formic acid (HCO₂H) is 1.8x10^-4?

A) K_b = K_w x K_a
B) K_b = K_a/K_w
C) K_b = K_w/K_a
D) K_b = K_w + K_a
E) K_b = K_w - K_a

Question 69

The base-ionization constants for three bases, A(OH), B(OH), and C(OH), are 1.8 x 10^-5, 4.4 x 10^-4, and 7.4 x 10^-4, respectively. Solutions of the bases having equal molarity have pH values that decrease in the following order:

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

Question 70

There are many ways of "fluoridating" water. One approach involves adding a salt of the fluoride ion, such as NaF. Calculate the pH of a 0.15 M NaF solution. (HF: K_a = 7.2 x 10^-4)

A) 2
B) 5.8
C) 8.2
D) 10.9
E) 12

Question 71

Ammonia and the ammonium ion form a conjugate acid-base pair.
NH₃(aq) + H₂O(l) NH₄⁺(aq) + OH^-(aq)
Calculate the pH of 0.10 M NH₃ if K_a for the NH₄⁺ ion is 5.6 x 10^-10.

A) 4.7
B) 5.1
C) 5.7
D) 8.9
E) 11.1

Question 72

Calculate the pH of a solution prepared by dissolving 1.00 x 10^-2 moles of sodium hypochlorite (NaOCl) in enough water to produce a 1.00 L of solution. Hypochlorous acid is a weak monoprotic acid with K_a = 3.2 x 10^-8.

A) 4.3
B) 4.7
C) 7.5
D) 9.3
E) 9.7

Question 73

What is the OH^- ion concentration in a 0.200 M NaOAc solution?
(HOAc: K_a = 1.8 x 10^-5)

A) 1.1 x 10^-10
B) 5.7 x 10^-10
C) 1.8 x 10^-6
D) 1.1 x 10^-5
E) 1.3 x 10^-3

Question 74

What is the H₃O⁺ ion concentration in a 0.10 M NH₃ solution?
(K_b = 1.8 x 10^-5)

A) 7.5 x 10^-10
B) 3.0 x 10^-10
C) 1.8 x 10^-6
D) 1.3 x 10^-3
E) none of these

Question 75

HA is a weak monoprotic acid with K_a = 2.4 x 10^-6. What is [OH^-] in a 0.300 M solution of the salt, NaA?

A) 5.8 x 10^-12
B) 2.4 x 10^-10
C) 3.5 x 10^-5
D) 6.5 x 10^-5
E) 1.6 x 10^-3

Question 76

Which of the following solutions would have a pH greater than 7.0?

A) NH₄Cl
B) NaCl
C) CH₃COOH
D) CH₃COONa
E) HCl

Question 77

Which of the following solutions has a pH greater than 7.0?

A) 0.10 M NH₄Cl
B) 0.10 M NH₄NO₃
C) 0.10 M HCN
D) 0.10 M NaCN
E) none of these

Question 78

Predict the products of the following acid-base reaction.
NH₄Cl(aq) + NaSH(aq)

Question 79

Which of the following solutions has the highest pH?

A) 0.3 M Na₂CO₃
B) 1 M HOAc
C) 0.3 M NH₄Cl
D) water
E) 10^-3 M HCl

Question 80

The addition of sodium formate (HCO₂Na) to a solution containing formic acid (HCO₂H: K_a = 1.8 x 10^-4) will cause

A) the pH to increase.
B) the pH to decrease.
C) no change in pH.
D) a change in the pH, the direction of which cannot be predicted.