Deck 7: Acids, Bases, and Equilibrium

Question 1

Which of the following is not a common characteristic of an acid?

A) it turns litmus pink/red
B) it tastes bitter
C) it dissolves common metals
D) all of these choices are common characteristics of acids

Answer 1

it tastes bitter

Question 2

Which of the following is not a common characteristic of a base?

A) it turns litmus pink/red
B) it feels slippery
C) it tastes bitter
D) all of these choices are common characteristics of bases

Answer 2

it turns litmus pink/red

Question 3

One characteristic of basic solution is that

A) the solution would turn litmus red.
B) the solution would have a slippery feel to it.
C) the solution would have a sour taste.
D) the solution would dissolve some metals.

Answer 3

the solution would have a slippery feel to it.

Question 4

A conjugate acid-base pair

A) is related by the loss and gain of H⁺ between 2 corresponding compounds on opposite sides of the reaction arrow.
B) has the base donating an H⁺ to form its conjugate base.
C) has the acid donating an H⁺ to form its conjugate acid.
D) is not related in any way.

Question 5

Which of the following is the conjugate acid of NH₃?

A) NH₂^-
B) NH₄⁺
C) HNO₃
D) H₃O⁺

Question 6

In the reaction:
The conjugate acid of water is ___.

A) HNO₂
B) H₂O
C) H₃O⁺
D) NO₂^-

Question 7

In the reaction:
NO₂^- is the

A) conjugate base of H₂O.
B) conjugate base of HNO₂.
C) conjugate acid of HNO₂.
D) conjugate base of H₃O⁺.

Question 8

Which of the following is the conjugate base of the acid, carbonic acid?

A) H₂CO₃
B) H₂O
C) H₃O⁺
D) HCO₃^-

Question 9

Hydrogen sulfide ion, HS^-, can react differently depending on the acidity of the solution in which it is present.
These two solutions show that the

A) hydrogen sulfide ion is an acid.
B) hydrogen sulfide ion is a base.
C) hydrogen sulfide ion is amphoteric.
D) hydrogen sulfide ion can only react with water.

Question 10

Which of the following is the conjugate acid of the bicarbonate ion, HCO₃^-?

A) H₂CO₃
B) CO₃^2-
C) CO₂
D) H₃O⁺

Question 11

Which of the following is the conjugate base of the bicarbonate ion, HCO₃^-?

A) H₂CO₃
B) CO₃^2-
C) CO₂
D) H₃O⁺

Question 12

In the equation:

A) H₂CO₃ and H₃O⁺ are conjugate pairs
B) H₂CO₃ is not amphoteric
C) H₂CO₃ and HCO₃ ^- are conjugate pairs
D) H₂CO₃ and H₂O are conjugate pairs

Question 13

Which of the following is the correct statement concerning the equation below?

A) HSO₄^- is the conjugate base of SO₄^-
B) HSO₄^- is the conjugate base of H₃O⁺
C) H₂O is the conjugate base of HSO₄^-
D) SO₄^2- is the conjugate base of HSO₄^-

Question 14

Whenever an equilibrium constant, K_eq, has a value greater than 1, which of the following statements is true at equilibrium?

A) The concentration of reactants is greater than the concentration of the products.
B) The concentration of products is the same as the concentration of reactants.
C) The concentration of the products is greater than the concentration of the reactants.
D) Relative composition of reaction mixture cannot be predicted.

Question 15

When a reaction is at equilibrium,

A) it has no products.
B) the rate of the forward reaction is equal to the rate of its reverse.
C) it occurs very quickly using up all of the reactants.
D) it produces the same amount of product as reactant.

Question 16

Choose the equilibrium constant that indicates the greatest relative amount of reactant concentration at equilibrium.

A) 1.1 x 10^-7
B) 2.3 x 10⁷
C) 6.7 x 10²
D) 8.3 x 10^-2

Question 17

The equation:
has the following equilibrium constant expression.

A)
B)
C)
D)

Question 18

The equilibrium constant, K_eq, for the ammonia synthesis below is found to be 6.0 x 10^-2 at 500 $\degree$ C. Which of the following statements is true at equilibrium?

A) Product concentration is greater than reactant concentration.
B) Reactant concentration is greater than product concentration.
C) Reactant concentration is the same as product concentration.
D) Relative concentrations of reactants and products cannot be predicted.

Question 19

The equilibrium constant K_eq for the reaction of molecular hydrogen and molecular iodine in the gas phase is 54.3 at 430 $\degree$ C.
Which of the following statements is true for this reaction at equilibrium?

A) The reactant concentration is larger than the product concentration.
B) The product concentration is larger than the reactant concentration.
C) The reactant concentration is the same as the product concentration.
D) None of these answer choices are correct.

Question 20

When stress is applied to a system at equilibrium such that the equilibrium is disturbed, the reaction proceeds in the direction that counteracts the disturbance. This explanation best describes ___.

A) Brønsted-Lowry concept
B) Ion-Ion attraction
C) Conjugate pair analysis
D) Le Châtelier's principle

Question 21

The equation:
has the following equilibrium constant expression:

A)
B)
C)
D)

Question 22

The effect of a catalyst on an equilibrium is

A) to speed up the reaction to the left.
B) to speed up the reaction to the right.
C) to speed up the reaction equally in both directions.
D) to shift the reaction in the direction of the catalyst.

Question 23

In the Haber process for the production of ammonia,
Which will not increase the amount of ammonia at equilibrium?

A) increasing the concentration of N₂
B) increasing the concentration of H₂
C) increasing the concentration of N₂ and H₂
D) addition of a catalyst

Question 24

Which of the conditions below would drive this reaction to the right?

A) removing hydronium ion
B) adding lactic acid
C) adding water
D) adding pyruvic acid

Question 25

Which of the following statements is true?

A) A catalyst used in a system that reaches a point of equilibrium decreases the reverse reactions and increases the forward reactions.
B) A catalyst used in a reversible reaction decreases the forward reactions but increases the reverse reactions.
C) A catalyst used in a reversible reaction increases the rate of both the forward and reverse reactions to the same extent but does not change the point of equilibrium.
D) A catalyst used in a system that reaches a point of equilibrium changes the point of equilibrium and decreases the rate of forward reactions only.

Question 26

In the reaction below:
Increasing the concentration of Cl₂ will ___ at equilibrium.

A) increase the concentration of PCl₅
B) increase the concentration of PCl₃
C) decrease the concentration of PCl₅
D) have no effect

Question 27

What is the concentration of [H₃O⁺] in an aqueous solution when the [OH^-] is 5.2 x 10^-9 M?

A) 1.9 x 10^-6 M
B) 5.7 M
C) 1.0 x 10^-14 M
D) 9.8 x 10^-9 M

Question 28

Calculate the [OH^-] in an aqueous solution when the [H₃O⁺] is 1.2 x 10^-2M.

A) 3.8 x 10^-10 M
B) 8.3 x 10^-11 M
C) 2.0 x 10^-10 M
D) 1.0 x 10^-14 M

Question 29

K_w, the equilibrium constant for the ionization of water by the equation below, is 1.0 x 10^-14. What does that mean when we are considering pure water?

A) More ions exist than water molecules.
B) The majority of the molecules present are in the form of H₂O.
C) The amount of water is the same as the amount of the ions present.
D) There will always be more hydronium ions present than water at equilibrium.

Question 30

A solution in which the concentration of H⁺ is greater than the concentration of OH^- will

A) have a pH greater than 7.0 and be basic.
B) have a pH less than 7.0 and be basic.
C) have a pH greater than 7.0 and be acidic.
D) have a pH less than 7.0 and be acidic.

Question 31

Basic solutions have an H⁺ concentration

A) greater than the OH^- concentration and a pH greater than 7.0.
B) greater than the OH^- concentration and a pH less than 7.0.
C) less than the OH^- concentration and a pH greater than 7.0.
D) less than the OH^- concentration and a pH less than 7.0.

Question 32

Acidic solutions have an H⁺ concentration

A) greater than the OH^- concentration and a pH greater than 7.0.
B) greater than the OH^- concentration and a pH less than 7.0.
C) less than the OH^- concentration and a pH greater than 7.0.
D) less than the OH^- concentration and a pH less than 7.0.

Question 33

One liter of a solution is found to contain 0.022 moles of HCl. Calculate the pH of the solution. Assume complete dissociation.

A) pH = 0.022
B) pH = 1.00
C) pH = 2.2
D) pH = 1.66

Question 34

When one is referring to pH, what is the meaning of the p?

A) Take the log of the number.
B) Multiply the p constant by the number.
C) Take the negative log of the number.
D) All are possible depending on the number following the p.

Question 35

What is the pH of a solution in which [H₃O]⁺ is 2.2 x 10^-12 M?

A) 2.34
B) 4.54 x 10^-3
C) 11.66
D) 8.42

Question 36

When we talk about pH we are referring to the concentration of hydronium ions present. If the concentration of hydronium in a solution is 1.0 x 10^-8 M, what is the hydroxide ion concentration?

A) 1.0 x 10^-6 M
B) 9.0 x 10^-8 M
C) 1.0 x 10^-14 M
D) The concentration cannot be predicted.

Question 37

Calculate the pH of solution produced by dissolving 0.001 moles of HNO₃ in a liter of water. Assume complete dissociation.

A) pH = 3.0
B) pH = 0.001
C) pH = 1 x 10^-3
D) pH = 1 x 10³

Question 38

What is the molar concentration of hydronium ions in a sample of a soft drink that has a pH of 4?

A) ¹/₄ M
B) 4 M
C) 1 x 10⁴ M
D) 1 x 10^-4 M

Question 39

You produce 500 mL of a 0.001 M HClO₄, which ionizes completely in water. What is the pH you should expect?

A) pH = 0.5
B) pH = 3.0
C) pH = 2.7
D) pH = 500

Question 40

A sample of orange juice has a pH of 3.44. Its [H₃O⁺] is ___.

A) 5.4 x 10^-1 M
B) 3.6 x 10^-4 M
C) 1.8 x 10^-5
D) 2.7 x 10^-3

Question 41

What is the [H₃O⁺] of an antacid tablet solution with a pH of 8.32?

A) 4.8 x 10^-9 M
B) 5.7 x 10^-9 M
C) 2.4 x 10-7 M
D) 1.2 x 10^-6 M

Question 42

Calculate the pH of a solution containing 0.15 moles KOH dissolved in enough water to produce 2 liters of solution.

A) pH = 0.075
B) pH = 0.15
C) pH = 1.12
D) pH = 12.88

Question 43

A K_a can be calculated for some chemical reactions. The K_a is

A) the K_eq for the reaction to the right.
B) the K_eq for the reaction to the left.
C) the K_eq for the dissociation of an acid.
D) the pH of a very weak solution.

Question 44

Which of the following statements is true?

A) The larger the K_a for an acid, the weaker the acid.
B) The smaller the pK_a of an acid, the stronger the acid.
C) The larger the pK_a of an acid, the stronger the acid.
D) The smaller the K_a, the stronger the acid.

Question 45

What is the [OH^-] of a solution whose pH is 3.00?

A) 1.0 x 10^-3 M
B) 1.0 x 10^-14 M
C) 1.0 x 10^-11 M
D) 1.0 x 10^-12 M

Question 46

Which material would be effective for neutralizing a minor acid spill?

A) soap solution
B) vinegar solution
C) baking soda
D) household ammonia

Question 47

15.00 mL of 0.100 M NaOH is required to completely neutralize 25.00 mL of an HCl solution. What is the concentration of the HCl solution?

A) 0.0600 M
B) 0.100 M
C) 0.167 M
D) 1.50 M

Question 48

What volume of 0.200 M HCl is required to completely neutralize 50.00 mL of 0.150 M KOH?

A) 7.50 mL
B) 50.0 mL
C) 66.7 mL
D) 37.5 mL

Question 49

The pH of blood is held reasonably stable by which buffer system?

A) H₃PO₄/H₂PO₄^-
B) NaCl/Cl^-
C) H₂CO₃/HCO₃^-
D) HCl/Cl^-

Question 50

Excessive use of antacids can lead to

A) an increase in blood pH known as acidosis.
B) an increase in blood pH known as alkalosis.
C) a decrease in blood pH know as acidosis.
D) a decrease in blood pH known as alkylosis.

Question 51

The ethylammonium ion, CH₃CH₂NH₃⁺ has a pK_a of 10.81. It reacts with water to form ethylamine, CH₃CH₂NH₂ and H₃O⁺ as shown below.
Which of the following statements is true at pH 7?

A) ethylammonium ion predominates
B) ethylamine predominates
C) the concentration of ethylamine equals that of ethylammonium ion
D) the pH is higher than pK_a of the ethylammonium ion

Question 52

The carbonic acid/bicarbonate buffer is important in maintaining the proper pH of human blood.
Diarrhea can lead to the loss of HCO₃^-. According to LeChatelier's principle, removal of HCO₃^- will shift the above equilibrium to the ___ and result in a(n) ___ in blood pH.

A) left/decrease
B) right/decrease
C) left/increase
D) right/increase

Question 53

The K_a for the reaction of acetic acid and water shown below is 1.8 x 10^-5.
Which of the following statements is true at pH 7?

A) there is much more acetic acid than acetate ion
B) there is more acetate ion than acetic acid
C) the concentration of acetate ion is equal to that of acetic acid
D) the pH is lower than pK_a of acetic acid

Question 54

The pH of blood is maintained at 7.35-7.45 by the following buffer system:
The H₂CO₃ is produced by the reaction of CO₂ with water according to the equation:
When one exercises, there is increased cellular output of CO₂. What effect will this have on the pH of the blood if the excess CO₂ is not eliminated?

A) The pH will increase.
B) The pH will decrease.
C) The pH will remain the same.
D) It is impossible to predict the effect.

Question 55

Antacids may contain which ion to reduce acidity?

A) Na⁺
B) CO₃^2-
C) Al³⁺
D) Cl^-

Question 56

Acids and bases can react with and damage many compounds that are vital to living organisms.

Question 57

HNO₃ can act as acid and as a base.

Question 58

The higher the numerical value of an equilibrium constant (K_eq), the further to the right the reaction will proceed.

Question 59

The greater the hydronium ion concentration, the higher the pH.

Question 60

For a buffer to continue to work effectively, the pH of a buffer has to be close to the pK_a of the conjugate acid.

Question 61

A buffer is capable of reducing the effect of the addition of small amounts of hydronium or hydroxide ion to a solution.

Question 62

If a wine has fermented beyond the step that produces alcohol, it becomes acidic, making the wine taste ___.

Question 63

Basic substances tend to have a ___ taste.

Question 64

The formula of the conjugate base of HClO₄ is ___.

Question 65

A base is a compound that produces an ion with the formula ___ in aqueous solution and an acid is a compound that produces the ___ ion in aqueous solution, which is also written as the hydronium ion (___).

Question 66

Compounds that can act as acids and bases are called ___.

Question 67

The conjugate base of the hydrogen sulfate ion (HSO₄^-) is ___.

Question 68

The conjugate acid of the hydrogen sulfate ion (HSO₄^-) is ___.

Question 69

In the following equation, identify the acid, base, conjugate acid, and conjugate base.

Question 70

Increasing the concentration of a ___ at equilibrium will drive the system toward the reactants.

Question 71

A is red, B is colorless, and C is yellow. Initially the system is in equilibrium and has an orange color.
What color will the system become if B is removed?

Question 72

A is red, B is colorless, and C is yellow. Initially the system is in equilibrium and has an orange color.
What color will the system become if B is added?

Question 73

A is red, B is colorless, and C is yellow. Initially the system is in equilibrium and has an orange color.
What color will the system become if it is heated?

Question 74

A is red, B is colorless, and C is yellow. Initially the system is in equilibrium and has an orange color.
What color will the system become if concentration of A is increased?

Question 75

A sample of blood has a pH of 7.37, which means that the sample of blood is slightly ___.

Question 76

Nitrous acid (HNO₂) has K_a = 4.0 x 10^-4, and carbonic acid (H₂CO₃) has K_a= 4.4 x 10^-7. The acid with a stronger conjugate base is ___

Question 77

The symptoms of alkalosis appear when blood serum pH is ___.

Question 78

____ is a condition in which the pH of blood is below the normal range.

Question 79

Which of the following are the strong acids? List all.
HF, HNO₃, HCN, CH₃COOH, H₂SO₄

Question 80

Calculate the pH of a 0.0019 M HNO₃ solution.