Deck 9: Acids and Bases, Ph, and Buffers

Question 1

Which solution has the highest concentration of [OH^-]?

A) a solution with a pH of 4
B) a solution with a pH of 10
C) a solution with a [H₃O⁺] of 6.8 × 10^-5 M
D) a solution with a [H₃O⁺] of 1 × 10^-13 M
E) a solution with a [OH^-] of 1 × 10^-2 M

Answer 1

a solution with a [H₃O⁺] of 1 × 10^-13 M

Question 2

A weak acid is also a _________ because it produces a low concentration of ions in solution.

A) weak electrolyte
B) strong electrolyte
C) nonelectrolyte
D) weak base
E) strong acid

Answer 2

weak electrolyte

Question 3

What mole ratio of NaOH to H₂SO₄ is needed in a neutralization reaction?

A) 1:1
B) 1:2
C) 1:3
D) 2:1
E) 3:1

Answer 3

2:1

Question 4

Which would be the BEST treatment of metabolic acidosis?

A) the IV administration of an acid
B) the IV administration of a weak base
C) breathing into a paper bag
D) the IV administration of HCl
E) reducing breathing rate

Question 5

Which molecule is amphoteric?

A) CH₃NH₂
B) CH₃OH
C) CH₃COOH
D) H₂SO₄
E) NaOH

Question 6

Which statement about neutralization reactions is FALSE?

A) Neutralization reactions occur between an acid and a base.
B) Neutralization reactions are equilibrium reactions.
C) Neutralization reactions produce water.
D) Neutralization reactions sometimes produce carbon dioxide.
E) Neutralization reactions always go to completion.

Question 7

Which of the following is a buffer system?

A) H₂CO₃ and HCO₃^-
B) NaCl and NaOH
C) HCl and NaOH
D) H₂O and HCl
E) NaCl and NaNO₃

Question 8

Which statement BEST describe a neutralization reaction?

A) An acid and base react to give a salt and sometimes water.
B) Two aqueous molecules react to give a liquid.
C) A positively charged ion reacts to give a neutral molecule.
D) An anion and a cation react to give a neutral molecule.
E) Two neutral molecules react to give a cation and an anion.

Question 9

Which statement does NOT correctly describe pH?

A) pH is a measure of acidity of a solution.
B) pH is a measure of hydronium concentration in a solution.
C) The higher the pH, the more acidic a solution.
D) A pH of 7 is a neutral solution.
E) pH = -log[H₃O⁺].

Question 10

Generally, strong bases are hydroxide salts of

A) transition metals.
B) the halogens.
C) alkali and alkaline earth metals.
D) the noble gases.
E) any element.

Question 11

Which of the following types of molecules and ions is NOT a base?

A) an anion
B) a cation
C) a neutral molecule containing a nonbonding pair of electrons
D) a tertiary nitrogen
E) All of these are bases.

Question 12

A blood sample has a pH of 7.42.What is the concentration of hydronium in the sample?

A) 0.87 M
B) 2.6 × 10⁷ M
C) -2.6 × 10⁷ M
D) 3.8 × 10⁸ M
E) 3.8 × 10^-8 M

Question 13

The following figure illustrates the action of a HF and F^- buffer where the sizes of the boxes are proportional to the concentrations of HF and F^- in solution.According to this figure, what happens when H₃O⁺ is added to the HF/F^- buffer?

A) The pH decreases.
B) The pH increases.
C) The concentration of HF increases.
D) The concentration of F^- increases.
E) Nothing happens.

Question 14

What is the concentration of H₃O⁺ and OH^- in pure water at room temperature?

A) 1.0 × 10^-14 M
B) 1.0 × 10^-7 M
C) 1.0 M
D) 1.0 × 10⁷ M
E) 1.0 × 10¹⁴ M

Question 15

Which solution has the highest concentration of [OH^-]?

A) a solution with a [H₃O⁺] of 1 × 10^-5 M
B) a solution with a [H₃O⁺] of 1 × 10^-13 M
C) a solution with a [OH^-] of 1 × 10^-5 M
D) a solution with a [OH^-] of 1 × 10^-13 M
E) a solution with a [OH^-] of 1 × 10^-2 M

Question 16

The boxed species in the following reaction is

A) a hydroxide.
B) a hydronium.
C) a proton.
D) the acid.
E) the conjugate base.

Question 17

The following figure illustrates the action of a HF and F^- buffer where the sizes of the boxes are proportional to the concentrations of HF and F^- in solution.What will happen when a small amount of base (OH^-)is added to the HF/F^- buffer?

A) The concentration of OH^- will increase.
B) The concentration of H₃O⁺ will increase.
C) The concentration of HF will increase.
D) The concentration of F^- will increase.
E) The pH of the solution will increase.

Question 18

A conjugate acid-base pair is

A) the reactants in an acid-base reaction.
B) the products of an acid-base reaction.
C) two species that differ only by a proton.
D) two species that differ only by a hydroxyl group.
E) a single molecule that can act as both an acid and a base.

Question 19

Which of the following statements does NOT describe a pH buffer?

A) A common buffer is a solution of acetic acid and acetate.
B) A buffer is a weak acid and the acid's conjugate base in equal concentrations.
C) A buffer is a physical barrier that blocks the addition of acid or base to a solution.
D) A buffer is a solution that resists change of pH upon addition of small amounts of acid or base.
E) Phosphates and bicarbonate are buffering systems in the body.

Question 20

Each circle is a sample of an aqueous acidic or basic solution.Which solution contains a strong acid?

A) figure a
B) figure b
C) figure c
D) figure d
E) figure e

Question 21

The concentration of H₃O⁺ in a solution is 1 × 10^-4 M.Which statement describes how the concentration of OH^- in the solution could be determined?

A) It is not possible to determine [OH^-].
B) Calculate pH.
C) Measure the pH with a pH probe or dipstick.
D) Solve for [OH^-] using the ion-product constant equation.
E) The [OH^-] is unchanged when an acid is added to a solution.

Question 22

Which equation BEST describes what will happen to formic acid when it reacts with water?

A) HCOOH (aq)+ 2 H₂O (l)→ CO₂^2- (aq)+ 2 H₃O⁺ (aq)
B) HCOOH (aq)+ H₂O (l)→ HCOOH₂⁺ (aq)+ OH^- (aq)
C) HCOOH (aq)+ H₂O (l)→ HCOO^- (aq)+ H₃O⁺ (aq)
D) HCOOH (aq)+ H₂O (l)→ H₂COOH (aq)+ OH^- (aq)
E) HCOOH (aq)+ H₂O (l)→ HCOO^- (aq)+ HO^- (aq)

Question 23

Select the choice that correctly states whether the substance is an acid or a base.

A) Vinegar is basic.
B) Amines are basic.
C) Gastric juice is basic.
D) Sodium hydroxide is acidic.
E) Soap is acidic.

Question 24

What is the pH of a solution with a [OH^- ] of 1.0 × 10^-10 M?

A) 1.0 × 10^-10
B) 10.0
C) 4.00
D) -10.0
E) -4.00

Question 25

The boxed species in the following reaction is

A) a hydroxide ion.
B) a hydronium ion.
C) a proton.
D) the acid.
E) the conjugate acid.

Question 26

If the concentration of hydronium ion in water is 1 × 10^-6 M, the concentration of hydroxide ion is _____ and there is more _____ in the solution.

A) 1 × 10^-8 M; hydroxide
B) 1 × 10^-8 M; hydronium
C) 1 × 10⁶ M; hydroxide
D) 1 × 10⁶ M; hydronium

Question 27

How do strong and weak acids differ?

A) Strong acids ionize completely in aqueous solution and weak acids don't.
B) Only strong acids produce hydronium in aqueous solution.
C) Strong acids donate protons and weak acids do not.
D) Strong acids increase the concentration of OH^- in solution.
E) Weak acids degrade less readily than strong acids.

Question 28

Which of the following statements about acids is FALSE?

A) An example of an acid is HBr.
B) An acid increases the concentration of hydroxide in solution.
C) An acid increases the concentration of protons in solution.
D) An acid increases the concentration of hydronium in solution.
E) An acid is a proton donor.

Question 29

The concentration of H₃O⁺ in a solution is 1 × 10^-4 M.What is the concentration of hydroxide ion in this solution?

A) 1 × 10^-10 M
B) 1 × 10^-8 M
C) 1 × 10^-12 M
D) 1 × 10^-7 M
E) 1 × 10¹⁰ M

Question 30

What is the pH of a solution with a [H₃O⁺] of 1.0 × 10^-5 M?

A) 9.00
B) 1.0 × 10^-5 M
C) -5.00
D) -9.00
E) 5.00

Question 31

Which of the following are conjugate acid-base pairs in the acid-base reaction between ethanamine and water? CH₃CH₂NH₂ (aq)+ H₂O (l)⇌ CH₃CH₂NH₃⁺ (aq)+ OH^- (aq)
I.H₂O and CH₃CH₂NH₂
II.H₂O and OH^-
III.CH₃CH₂NH₂ and CH₃CH₂NH₃⁺
IV.CH₃CH₂NH₃⁺ and OH^-

A) I only
B) I and IV
C) II only
D) II and IV
E) II and III

Question 32

Which statement does NOT correctly describe buffer capacity?

A) Buffer capacity is determined only by the identity of the buffer.
B) The addition of amounts of acid or base exceeding the buffer capacity will change the pH of the solution.
C) The higher the concentration of weak acid and conjugate base in solution, the higher the buffer capacity.
D) The greatest amount of acid or base that a buffer can accept while maintaining pH is called the buffer capacity.
E) Once the buffer capacity is exceeded in cells, key functions of the body can be disrupted.

Question 33

Which condition could cause respiratory acidosis?

A) hyperventilation
B) asthma
C) kidney failure
D) excessive vomiting
E) starvation

Question 34

What is the pH of a urine sample with a hydronium concentration of 7.9 × 10^-8?

A) -7.10
B) 7.10
C) 6.90
D) -6.90
E) 7.00

Question 35

Which change in blood pH would you expect to observe in a hyperventilating patient, and what are those changes called?

A) a drop in pH, alkalosis
B) a drop in pH, acidosis
C) an increase in pH, alkalosis
D) an increase in pH, acidosis
E) There will not be any change in blood pH.

Question 36

Which of the following reactions illustrate the reaction of a base? I.NH₃ + H₂O → NH₄⁺ + OH^-
II)HCl + H₂O → H₃O⁺ + Cl^-
III)NaOH → Na⁺ + OH^-
IV)NH₄⁺ + H₂O → H₃O⁺ + NH₃

A) I only
B) II only
C) I and III
D) I, III, and IV
E) All of the above are reactions of a base.

Question 37

What is the [H₃O⁺] in a solution that has a [OH^-] of 3.2 × 10^-4 M?

A) 3.2 × 10^-10 M
B) 3.2 × 10¹⁰ M
C) 3.1 × 10^-11 M
D) 3.1 × 10¹¹ M
E) 1.0 × 10^-7 M

Question 38

Which of the following statements BEST describes what happens when an acid reacts with water? I.The acid donates a proton.
II.Water donates a proton.
III.Water acts as a base.
IV.Hydronium is formed.
V.Hydroxide is formed.

A) I only
B) II only
C) I, III, and V
D) I, III, and IV
E) II and V

Question 39

The reaction between acetic acid and water is given below, followed by a list of changes that could be made to the reaction solution.Which change will result in the equilibrium shifting to the left? CH₃COOH + H₂O ⇌ CH₃COO^- + H₃O⁺
Changes that could be made to the solution
I.Adding more CH₃COOH
II.Removing H₂O
III.Removing H₃O⁺
IV.Adding more CH₃COO^-

A) All of these changes will result in the equilibrium shifting to the left.
B) Only I will result in the equilibrium shifting to the left.
C) Only IV will result in the equilibrium shifting to the left.
D) I and III will result in the equilibrium shifting to the left.
E) II and IV will result in the equilibrium shifting to the left.

Question 40

If the concentration of hydronium ion in water is 1 × 10^-12 M, the concentration of hydroxide ion is _____ and there is more _____ in the solution.

A) 1 × 10^-2 M; hydroxide
B) 1 × 10^-2 M; hydronium
C) 1 × 10¹² M; hydroxide
D) 1 × 10¹² M; hydronium

Question 41

Which species in the following neutralization reaction are spectator ions? NaOH + HCl → H₂O + NaCl

A) H₃O⁺
B) OH^-
C) H₂O
D) NaCl
E) H⁺

Question 42

What is the pH of a solution with a [OH^-] of 4.1 × 10^-3 M?

A) -2.39
B) 2.39
C) 11.6
D) -11.6
E) 7.00

Question 43

The following figure illustrates the action of a HF and F^- buffer where the sizes of the boxes are proportional to the concentrations of HF and F^- in solution.Which of the following chemical equations represents the reaction that occurs when OH^- is added to the HF/F^- buffer?

A) HF + H₂O ⇌ F^- + H₃O⁺
B) F^- + H₂O ⇌ F^- + OH^-
C) HF + OH^- ⇌ F^- + H₂O
D) F^- + 2 OH^- ⇌ HF + O₂
E) F^- + OH^- ⇌ HOF

Question 44

Which of the following atomic diagrams best represents H⁺?

A) figure a
B) figure b
C) figure c
D) figure d
E) figure e

Question 45

Water can react as both an acid and a base, depending on its environment.Because of this characteristic, water is a(n)_________ molecule.

A) amphoteric
B) autonomous
C) complex
D) reactive
E) conjugated

Question 46

Consider a buffer solution containing CH₃COO^-Na⁺ and CH₃COOH.If you add hydronium (H₃O⁺)until all of the CH₃COO^- is converted into CH₃COOH and then add a little more hydronium, what do you expect to observe?

A) The pH increases.
B) The pH decreases.
C) The pH stays the same.
D) The solution will be neutralized.
E) The pH changes, but it is not possible to determine how it will change.

Question 47

What happens to pH when the buffer capacity of a solution is exceeded?

A) The pH increases.
B) The pH decreases.
C) The solution will become unstable.
D) The pH will either increase or decrease, depending on whether acid or base is added to the solution.
E) The pH will not be changed.

Question 48

The neutralization reaction of potassium hydrogen carbonate (KHCO₃)and HI produces what spectator ion(s)?

A) CO₃^2-
B) K⁺ and I^-
C) HCO₃^-
D) H₃O⁺ and OH^-
E) H⁺

Question 49

Which of the following compounds is a Brønsted-Lowry base but not an Arrhenius base?

A) HCl
B) NaOH
C) NH₃
D) Ca(OH)₂
E) CH₃COOH

Question 50

The neutralization reaction of potassium hydrogen carbonate (KHCO₃)and HI produces what gas?

A) CO₂
B) O₂
C) H₂CO₃
D) H₂O
E) H⁺

Question 51

Which of the following statements about bases is FALSE?

A) A base decreases the concentration of hydronium in solution.
B) An example of a base is Ca(OH)₂.
C) A base increases the concentration of hydroxide in solution.
D) A base is a proton acceptor.
E) A base is always negatively charged.

Question 52

The boxed species in the following reaction is

A) a hydroxide.
B) a hydronium.
C) a proton.
D) the acid.
E) the base.

Question 53

Each circle is a sample of an aqueous acidic or basic solution.Which solution contains a weak base?

A) figure a
B) figure b
C) figure c
D) figure d
E) figure e

Question 54

The boxed species in the following reaction is

A) a hydroxide.
B) a hydronium.
C) a proton.
D) the acid.
E) the base.

Question 55

The following figure illustrates the action of a HF and F^- buffer where the sizes of the boxes are proportional to the concentrations of HF and F^- in solution.If you add hydronium until all of the F^- is converted into HF and then add a little more hydronium, what is observed?

A) The pH increases.
B) The pH decreases.
C) The pH stays the same.
D) The solution will be neutralized.
E) The pH changes, but it is not possible to determine how it will change.

Question 56

What is the role of the kidney in maintaining acid-base homeostasis in the blood?

A) removing excess CO₂
B) adding extra H⁺ as needed
C) adding/removing water
D) adding/removing hydrogen carbonate ion
E) All of the above are roles of the kidney.

Question 57

Which reaction BEST illustrates the reaction of an acid in aqueous solution?

A) HCl + H₂O → Cl^- + H₃O⁺
B) NH₃ + H₂O → ⁺NH₄ + H₃O⁺
C) HCl + H₂O → HCl + H₃O⁺
D) NH₃ + H₂O → ⁺NH₄ + HO^-
E) HCl + H₂O → Cl^- + HO^-

Question 58

What do all bases have in common?

A) They contain an OH^- group.
B) They contain a nitrogen.
C) They contain an oxygen.
D) They are salts.
E) They contain a nonbonding pair of electrons.

Question 59

Each circle is a sample of an aqueous acidic or basic solution.Which solution contains a weak acid?

A) figure a
B) figure b
C) figure c
D) figure d
E) figure e

Question 60

Which statement BEST describes the following reaction? HCOOH + H₂O ⇌ HCOO^- + H₃O⁺

A) This is the reaction of a strong acid.
B) This is the reaction of a weak acid.
C) This reaction is the dissociation of a strong base.
D) This is the reaction of a weak base.
E) This is not an acid-base reaction.

Question 61

Which of the following is a balanced equation for a neutralization reaction?

A) Al(OH)₃ (s)+ HCl (aq)→ 3 H₂O (l)+ AlCl₃ (aq)
B) Mg(OH)₂ (s)+ HNO₃ (aq)→ 2 H₂O (l)+ Mg(NO₃)₂ (aq)
C) Ca(OH)₂ (s)+ HNO₃ (aq)→ 2 H₂O (l)+ Ca(NO₃)₂ (aq)
D) KOH (s)+ HNO₃ (aq)→ H₂O (l)+ KNO₃ (aq)
E) 2 Al(OH)₃ (s)+ HCl (aq)→ 3 H₂O (l)+ AlCl₃ (aq)

Question 62

The boxed species in the following reaction is

A) a hydroxide.
B) a hydronium.
C) a proton.
D) the acid.
E) the conjugate base.

Question 63

Which molecule is a base?

A) molecule a
B) molecule b
C) molecule c
D) molecule d
E) molecule e

Question 64

Which base is a strong base?

A) LiOH
B) CH₃CH₂NH₂
C) NH₂CH₂COOH
D) NH₂CH₂CH₂CH₂NH₂
E) All of the above molecules are strong bases.

Question 65

Which strong acid is found in the body?

A) HNO₃
B) HCl
C) H₂SO₄
D) HClO₄
E) HBr

Question 66

Which acid is NOT a strong acid?

A) HCl
B) HI
C) HNO₃
D) CH₃COOH
E) H₂SO₄

Question 67

Which buffer system is the primary buffering system in the blood?

A) proteins
B) DNA and RNA
C) H₂PO₄^-/HPO₄^2-
D) H₂CO₃/HCO₃^-
E) CH₃COOH/CH₃COO^-

Question 68

The following reaction is a reversible reaction.Which statement BEST describes what it means for this reaction to be reversible? HCOOH + H₂O ⇌ HCOO^- + H₃O⁺

A) This reaction only occurs in the reverse direction as written above.
B) All of the reactant molecules react to make product and then all of the product molecules react to make reactants again.
C) Forward and reverse reactions proceed at the same rate.
D) Forward and reverse reactions occur simultaneously.
E) The rate of the reverse reaction is must faster than the rate of the forward reaction.

Question 69

A sample of gastric juice has a pH of 1.20.What is the concentration of hydroxide in this sample?

A) 1.6 × 10^-13 M
B) 6.3 × 10^-2 M
C) 1.0 × 10^-7 M
D) 6.3 × 10¹² M
E) 6.3 × 10^-16 M

Question 70

What is the pH of a solution with a [H₃O⁺] of 7.9 × 10^-11 M?

A) 10.1
B) -10.1
C) 3.90
D) -3.90
E) 11.9

Question 71

Which statement BEST describes the role of water in the reaction of ethanamine and water? CH₃CH₂NH₂ (aq)+ H₂O (l)⇌ CH₃CH₂NH₃⁺ (aq)+ OH^- (aq)

A) Water is the acid.
B) Water is the base.
C) Water is the conjugate acid.
D) Water is the conjugate base.
E) Water is both an acid and a base.

Question 72

The [H₃O⁺] of a solution with a pH of 2 is ______ the [H₃O⁺] of a solution with a pH of 3.

A) one-tenth
B) ten times
C) one-half
D) twice
E) the same as

Question 73

When an acid is dissolved in water, it reacts to give _________ and ________.

A) hydroxide; hydronium
B) hydronium; the conjugate acid
C) hydroxide; the conjugate acid
D) hydronium; the conjugate base
E) hydroxide; the conjugate base

Question 74

Which statement BEST describes what it means for the acid-base reaction between acetic acid and water to be in equilibrium? CH₃COOH + H₂O ⇌ CH₃COO^- + H₃O⁺

A) The mass of acetic acid and acetate is equal.
B) The number of moles of acetate equals the number of moles of acetic acid.
C) The number of moles of hydronium equals the number of moles of water.
D) The forward and reverse reactions proceed at the same rate.
E) The reaction is balanced.

Question 75

Which of the following equations is the correctly balanced equation for the neutralization reaction of aluminum hydroxide and HCl?

A) Al(OH)₃ (s)+ HCl (aq)→ 3 H₂O (l)+ AlCl₃ (aq)
B) 3 Al(OH)₃ (s)+ HCl (aq)→ 3 H₂O (l)+ AlCl₃ (aq)
C) Al(OH)₃ (s)+ 3 HCl (aq)→ 3 H₂O (l)+ AlCl₃ (aq)
D) Al(OH)₃ (s)+ HCl (aq)→ H₂O (l)+ AlCl₃ (aq)
E) 3 Al(OH)₃ (s)+ HCl (aq)→ 3 H₂O (l)+ 3 AlCl₃ (aq)

Question 76

What is the [OH^-] in a solution that has a [H₃O⁺] of 1 × 10^-6 M?

A) 1 × 10^-20 M
B) 1 × 10^-8 M
C) 1 × 10^-6 M
D) 1 × 10^-7 M
E) 1 × 10⁷ M

Question 77

Which pH range is referred to as physiological pH?

A) 6-8
B) 7.35-7.45
C) 6.7-6.8
D) 6.5-7.5
E) 5-8

Question 78

Which statement BEST describes the following reaction?

A) This is the reaction of a strong acid.
B) This is the reaction of a weak acid.
C) This reaction is the dissociation of a strong base.
D) This is the reaction of a weak base.
E) This is not an acid-base reaction.

Question 79

All acid-base reactions that we consider in this chapter occur in

A) acidic solution.
B) basic solution.
C) neutral solution.
D) aqueous solution.
E) nonpolar solvents.

Question 80

Each circle is a sample of an aqueous acidic or basic solution.Which solution contains a strong base?

A) figure a
B) figure b
C) figure c
D) figure d
E) figure e