Acids, Bases, and pH: Interactive Learning Quizzes for Biology Majors

Question 1

Which of the following is considered a strong acid at room temperature?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Question 2

Calculate the pH of a solution with a hydrogen ion concentration of 1 x 10^-4 M.

Accepted Answer

4

Answer

7

Answer

10

Question 3

Identify the substance that behaves as a base in aqueous solutions.

Accepted Answer

Ammonia

Answer

Sodium chloride

Answer

Hydrochloric acid

Question 4

What is the conjugate base of a weak acid?

Accepted Answer

A weak base

Answer

A strong base

Answer

A strong acid

Question 5

What is the pOH of a solution with a pH of 5?

Accepted Answer

9

Answer

5

Answer

14

Question 6

Which of the following is classified as a strong electrolyte?

Accepted Answer

Sodium chloride

Answer

Glucose

Answer

Acetic acid

Question 7

What is the neutral pH of a solution at room temperature?

Accepted Answer

=7

Answer

<7

Answer

>7

Question 8

Identify the solution that acts as a buffer solution.

Accepted Answer

A mixture of a weak acid and its conjugate base

Answer

Pure water

Answer

A mixture of a strong acid and a strong base

Question 9

According to the Arrhenius definition, an acid is a substance that:

Accepted Answer

Donates protons (H+ ions)

Answer

Releases hydroxide ions (OH-)

Answer

Neutralizes acids

Answer

Accepts protons (H+ ions)

Question 10

Which of the following is a strong base?

Accepted Answer

Sodium hydroxide (NaOH)

Answer

Carbonic acid (H2CO3)

Answer

Ammonia (NH3)

Answer

Acetic acid (CH3COOH)

Question 11

The conjugate acid of the bicarbonate ion (HCO3-) is:

Accepted Answer

Hydrogen carbonate (H2CO3)

Answer

Hydroxide ion (OH-)

Answer

Carbonic acid (H2O3)

Answer

Water (H2O)

Question 12

Which of the following reactions is an acid-base neutralization reaction?

Accepted Answer

H2SO4 + 2NaOH → Na2SO4 + 2H2O

Answer

NaOH + NaOH → Na2O + H2

Answer

CaCO3 + 2HCl → CaCl2 + CO2 + H2O

Answer

HCl + Na2SO4 → NaCl + H2SO4

Question 13

The buffer capacity of a solution refers to its:

Accepted Answer

Ability to resist changes in pH upon addition of acids or bases

Answer

Concentration of acid or base present

Answer

pH of the solution

Answer

Number of moles of acid or base that can be added before the pH changes

Question 14

The pH scale is primarily used to measure:

Accepted Answer

The acidity or basicity of a solution

Answer

The temperature of a solution

Answer

The concentration of ions in a solution

Answer

The solubility of a substance

Question 15

Pepsin, an enzyme that works best at a pH of 2, is put in a setting with a higher pH. How will this likely affect its activity?

Accepted Answer

Decreased activity

Answer

Increased activity

Answer

No change in activity

Question 16

Identify the strong base in the following list:

Accepted Answer

Sodium hydroxide (NaOH)

Answer

Ammonium hydroxide (NH4OH)

Answer

Acetic acid (CH3COOH)

Answer

Hydrochloric acid (HCl)

Question 17

What is the pH value of a neutral solution?

Accepted Answer

7

Answer

0

Answer

14

Answer

10

Question 18

Which of the provided reactions represents an acid-base reaction?

Accepted Answer

NaOH + HCl → NaCl + H2O

Answer

Fe + 2HCl → FeCl2 + H2

Answer

2Na + Cl2 → 2NaCl

Answer

CH3OH + O2 → CH3COOH + H2O

Question 19

What is the molarity of a solution containing 0.1 moles of solute dissolved in 1 liter of solution?

Accepted Answer

0.1 M

Answer

0.01 M

Answer

1.0 M

Answer

10 M

Question 20

Which of the following correctly describes a buffer solution?

Accepted Answer

A solution that maintains its pH despite the addition of small amounts of acid or base

Answer

A solution containing a weak acid and its conjugate base

Answer

A solution containing a strong acid and a strong base

Answer

A solution with a pH of 7

Question 21

Identify the conjugate base of H2SO4:

Accepted Answer

SO42-

Answer

HSO4-

Answer

H3O+

Answer

OH-

Question 22

Which compound is classified as a weak electrolyte?

Accepted Answer

Acetic acid (CH3COOH)

Answer

Hydrochloric acid (HCl)

Answer

Sodium chloride (NaCl)

Answer

Potassium hydroxide (KOH)

Question 23

Provide the definition of pH that expresses its measurement in terms of a logarithmic scale.

Accepted Answer

The logarithmic scale representing the acidity or alkalinity of a solution

Answer

The quantity of hydrogen ions present in a solution

Answer

The ability of a solution to neutralize either an acid or a base

Answer

The concentration of hydroxide ions in a solution

Question 24

Identify the strong acid from the following list.

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Phosphoric acid

Question 25

Which of the following is a weak base?

Accepted Answer

Ammonia

Answer

Sodium hydroxide

Answer

Potassium hydroxide

Answer

Calcium hydroxide

Question 26

Determine the pH value of a neutral solution.

Accepted Answer

7

Answer

0

Answer

14

Answer

2

Question 27

Identify the acid-base neutralization reaction among the given options.

Accepted Answer

HCl + NaOH → NaCl + H2O

Answer

2Na + Cl2 → 2NaCl

Answer

CuSO4 + H2SO4 → CuSO4·H2SO4

Answer

CH3COOH + C2H5OH → CH3COOC2H5 + H2O

Question 28

Determine the conjugate base of H2SO4.

Accepted Answer

SO42-

Answer

HSO4-

Answer

OH-

Answer

H3O+

Question 29

Identify the most effective buffer system for resisting pH changes.

Accepted Answer

Weak acid/weak base

Answer

Weak acid/strong base

Answer

Strong acid/weak base

Answer

Strong acid/strong base

Question 30

Which factor primarily determines the buffer capacity of a solution?

Accepted Answer

Concentration of the weak acid and its conjugate base

Answer

pH of the solution

Answer

Temperature of the solution

Answer

Volume of the solution

Question 31

How does pH impact enzyme activity and protein structure, and why is this important in cellular processes?

Accepted Answer

pH alters the ionization of amino acids in proteins, affecting enzyme activity and protein shape.

Answer

pH only affects enzyme activity, not protein structure.

Answer

pH is the primary determinant of cellular processes.

Question 32

What is autoionization, and how does it impact the properties of water?

Accepted Answer

Autoionization is a reaction where water molecules exchange protons, forming equal amounts of hydrogen (H+) and hydroxide (OH-) ions.

Answer

Autoionization is a process where water molecules gain protons from each other.

Answer

Autoionization only occurs in water and not in other solvents.

Answer

Autoionization is when water molecules break down into hydrogen and oxygen gas.

Question 33

How does pH affect the solubility of ionic compounds? Provide specific examples of its applications in precipitation and extraction.

Accepted Answer

pH influences solubility by controlling the formation of precipitates and the ionization of weak acids and bases.

Answer

pH has no effect on solubility; ionic compounds are always soluble.

Answer

pH increases solubility by promoting the ionization of ionic compounds.

Answer

pH does not affect solubility; it only influences the reaction rates involving ionic compounds.

Question 34

Which of the following statements regarding acids is incorrect?

Accepted Answer

Acids turn litmus paper blue.

Answer

Acids have a sour taste.

Answer

Acids react with metals to release hydrogen gas.

Answer

Acids are corrosive.

Question 35

Which of the following is a weak acid?

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Sulfuric acid

Answer

Nitric acid

Question 36

The conjugate base of a weak acid is:

Accepted Answer

A weak base

Answer

A strong base

Answer

A neutral compound

Answer

An acid

Question 37

A buffer solution is defined as:

Accepted Answer

A solution that resists changes in pH when small amounts of acid or base are added

Answer

A solution with a pH of 7

Answer

A solution that has a high concentration of hydrogen ions

Answer

A solution that has a low concentration of hydroxide ions

Question 38

What is the pOH of a solution with a pH of 5?

Accepted Answer

9

Answer

5

Answer

4

Answer

7

Question 39

A titration is:

Accepted Answer

A process of adding a known amount of a reagent to a solution of unknown concentration

Answer

A process of measuring the pH of a solution

Answer

A process of neutralizing an acid with a base

Answer

A process of separating a mixture using chromatography

Question 40

The molarity of a solution prepared by dissolving 0.1 moles of NaOH in 1 liter of water is:

Accepted Answer

0.1 M

Answer

0.05 M

Answer

0.2 M

Answer

0.4 M

Question 41

According to the Brønsted-Lowry theory, a base is a substance that:

Accepted Answer

Accepts protons in a chemical reaction.

Answer

Donates protons in a chemical reaction.

Answer

Increases the pH of a solution.

Answer

Decreases the pH of a solution.

Question 42

Which of the following is a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Phosphoric acid

Question 43

What is the conjugate base of H2SO4?

Accepted Answer

SO42-

Answer

HSO4-

Answer

OH-

Answer

H3O+

Question 44

Which of the following reactions is an acid-base neutralization reaction?

Accepted Answer

NaOH + HCl → NaCl + H2O

Answer

CuSO4 + H2O → Cu(OH)2 + H2SO4

Answer

NH3 + H2O → NH4+ + OH-

Answer

2NaCl + 2H2O → 2NaOH + 2HCl

Question 45

What is the primary role of a buffer solution in biological systems?

Accepted Answer

To maintain a stable pH despite the addition of small amounts of acid or base.

Answer

To increase the rate of chemical reactions.

Answer

To decrease the solubility of solutes.

Answer

To change the color of solutions.

Question 46

Which of the following is a Lewis acid?

Accepted Answer

BF3

Answer

HCl

Answer

NaOH

Answer

NH3

Question 47

What is the approximate pH of human blood?

Accepted Answer

7.4

Answer

Two

Answer

Five

Answer

Nine

Question 48

Which of the following statements correctly defines an acid?

Accepted Answer

A substance that donates protons (H+ ions)

Answer

A substance that increases the pH of a solution

Answer

A substance that accepts electrons

Question 49

The pH of a solution is 4.5. What is the concentration of H+ ions in this solution?

Accepted Answer

3.16 x 10^-5 M

Answer

6.31 x 10^-10 M

Answer

3.16 x 10^-4 M

Question 50

Which of the following compounds is a strong base?

Accepted Answer

NaOH

Answer

H2CO3

Answer

NH3

Answer

CH3COOH