Acids, Bases, and Redox Reactions Quizzes | Chemistry Year 12

Question 1

What is the conjugate base of sulfuric acid (H2SO4)?

Accepted Answer

Sulfate ion (SO42-)

Answer

Hydrogen sulfate ion (HSO4-)

Answer

Hydronium ion (H3O+)

Answer

Hydroxide ion (OH-)

Question 2

Which expression represents the pH of a buffer solution?

Accepted Answer

pH = pKa + log([A-]/[HA])

Answer

pH = -log[H+]

Answer

pH = [H+]/[OH-]

Answer

pH = Ka/[H+]

Question 3

Determine the pH of a solution formed by combining 25.0 mL of 0.10 M HCl with 25.0 mL of 0.10 M NaOH. Explain your reasoning.

Accepted Answer

7.00

Answer

1.00

Answer

10.00

Answer

12.00

Question 4

Which of the following is the conjugate base of the acid HSO4-?

Accepted Answer

SO42-

Answer

H2SO4

Answer

H3O+

Answer

OH-

Question 5

Which of the following statements about buffer solutions is **false**?

Accepted Answer

Buffer solutions have a limited capacity to neutralize acids and bases.

Answer

Buffer solutions resist changes in pH when small amounts of acid or base are added.

Answer

The pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation.

Answer

Buffer solutions are typically composed of a weak acid and its conjugate base.

Question 6

Which of the following best describes the characteristics of a buffer solution?

Accepted Answer

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

Answer

A solution with a pH of exactly 7.0.

Answer

A solution that contains a strong acid and a strong base.

Answer

A solution that has a high concentration of hydrogen ions.

Question 7

What is the conjugate acid of the base NH3?

Accepted Answer

NH4+

Answer

H2O

Answer

OH-

Answer

H+

Question 8

What is the conjugate acid-base pair for ammonia (NH3)?

Accepted Answer

NH3, NH4+

Answer

NH4+, NH2-

Answer

H+, NH3

Answer

OH-, NH4+

Question 9

Which acid among the following has the greatest concentration of hydrogen ions (H+)?

Accepted Answer

HCl

Answer

H2O

Answer

CH3COOH

Answer

NH3

Question 10

In the Bronsted-Lowry theory, which species is the strongest base?

Accepted Answer

OH-

Answer

H2O

Answer

NH3

Answer

CH3COO-

Question 11

In the reaction: NH3 + H2O <=> NH4+ + OH-, which species is the conjugate acid of NH3?

Accepted Answer

NH4+

Answer

NH3

Answer

H2O

Answer

OH-

Question 12

Calculate the equilibrium constant, Kc, for the following reaction:

2NO(g) + O2(g) <=> 2NO2(g)

Accepted Answer

Kc = [NO2]^2/[NO]^2[O2]

Answer

Kc = [NO]^2[O2]/[NO2]^2

Answer

Kc = [NO]^2 + [O2]/[NO2]^2

Answer

Kc = [NO2]^2 + [O2]/[NO]^2

Question 13

Which of these is a strong acid?

Accepted Answer

H2SO4 (Sulfuric acid)

Answer

CH3COOH (Ethanoic acid)

Answer

NaOH (Sodium hydroxide)

Answer

H2O (Water)

Question 14

According to the Bronsted-Lowry theory, which of the following is an acid?

Accepted Answer

HCl

Answer

H2O

Answer

NH3

Answer

CH3OH

Question 15

In a Bronsted-Lowry acid-base reaction, what particle is transferred from the acid to the base?

Accepted Answer

Proton (H+)

Answer

Electron

Answer

Neutron

Answer

Electron pair

Question 16

According to the Bronsted-Lowry theory, what is the conjugate acid of NH3?

Accepted Answer

NH4+

Answer

H3O+

Answer

OH-

Answer

H2O

Question 17

In the Bronsted-Lowry theory, what is the conjugate acid of ammonia (NH3)?

Accepted Answer

NH4+

Answer

H2O

Answer

OH-

Answer

H3O+

Question 18

To determine the acidity or alkalinity of an aqueous solution, we use pH. Which formula is used to calculate the pH of an aqueous solution?

Accepted Answer

-log[H+]

Answer

log([H+]/[OH-])

Answer

[H+] + [OH-]

Answer

log([OH-])

Question 19

Which characteristic of a buffer solution allows it to resist pH changes when small amounts of acid or base are added?

Accepted Answer

Contains a weak acid and its conjugate base or a weak base and its conjugate acid

Answer

Has a high molarity of either the weak acid or its conjugate base

Answer

Has a pH that is highly sensitive to the addition of small amounts of acid or base

Answer

Has a pH that is always equal to the pKa of the weak acid or base

Question 20

Identify the conjugate acid of HSO4-.

Accepted Answer

H2SO4

Answer

SO42-

Answer

OH-

Answer

H3O+

Question 21

In an acid-base titration, what is the main purpose of an indicator?

Accepted Answer

To indicate the endpoint by changing color

Answer

To neutralize the acid

Answer

To speed up the titration

Answer

To cancel out the acid's color

Question 22

Which property is NOT characteristic of an acidic solution?

Accepted Answer

Sweet taste

Answer

High concentration of H+ ions

Answer

Low pH value

Answer

Strong electrical conductivity

Question 23

Which species is the conjugate base of a weak acid?

Accepted Answer

A weak base

Answer

A strong acid

Answer

A strong base

Answer

A salt

Question 24

Which substance can act as an oxidizing agent?

Accepted Answer

Chlorine (Cl)

Answer

Zinc (Zn)

Answer

Hydrogen gas (H2)

Answer

Sodium ions (Na+)

Question 25

Which of the following species is a Lewis acid?

Accepted Answer

Boron trifluoride (BF3)

Answer

Ammonia (NH3)

Answer

Water (H2O)

Answer

Sodium hydroxide (NaOH)

Question 26

Which of the following reactions is considered spontaneous?

Accepted Answer

A reaction with a negative change in free energy (ΔG)

Answer

A reaction with a positive change in free energy (ΔG)

Answer

A reaction with a ΔG of 0

Answer

A reaction with a positive change in enthalpy (ΔH)

Question 27

What is the pH of a neutral solution at 25°C?

Accepted Answer

7

Answer

0

Answer

14

Answer

It varies depending on the temperature

Question 28

Which of the following is a reducing agent?

Accepted Answer

Hydrogen

Answer

Potassium permanganate

Answer

Oxygen

Answer

Copper(II) sulfate

Question 29

In a balanced redox reaction, the total number of electrons lost must be:

Accepted Answer

Equal to the total number of electrons gained

Answer

Less than the total number of electrons gained

Answer

Greater than the total number of electrons gained

Answer

Irrelevant to the balancing of the equation

Question 30

Calculate the molarity of a solution that contains 0.10 moles of solute in 500 milliliters of solution.

Accepted Answer

0.02 M

Answer

0.002 M

Answer

0.2 M

Answer

2 M

Question 31

Which of the following is a weak acid?

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Nitric acid

Answer

Sulfuric acid

Question 32

Which of the following is a buffer solution?

Accepted Answer

A solution that contains a weak acid and its conjugate base

Answer

A solution that contains a strong acid and its conjugate base

Answer

A solution that has a pH of 7

Answer

A solution that has a high concentration of ions

Question 33

What is the primary purpose of using an indicator in a titration?

Accepted Answer

To determine the point at which the reaction is complete (equivalence point)

Answer

To neutralize the solution

Answer

To speed up the reaction

Answer

To make the solution more acidic

Question 34

In a reaction between sodium carbonate (Na2CO3) and hydrochloric acid (HCl), what are the predicted products? Write the balanced chemical equation for this reaction.

Accepted Answer

Na2Cl, CO2, and H2O

Answer

Na2Cl and H2CO3

Answer

NaCl, NaHCO3, and CO2

Answer

NaHCO3 and H2O

Question 35

Which of the following redox reactions is balanced?

Accepted Answer

2Fe + 6HCl -> 2FeCl3 + 3H2

Answer

Fe + HCl -> FeCl2 + H2

Answer

Fe + 2HCl -> FeCl2 + H2O

Answer

Fe + 3HCl -> FeCl3 + H2 + Cl2

Question 36

In an electrochemical cell, what is the primary purpose of a salt bridge?

Accepted Answer

Maintaining electrical neutrality within the cell

Answer

Allowing electron flow between electrodes

Answer

Preventing the intermingling of half-cell solutions

Answer

Supplying ions to the electrodes

Question 37

Which of the following acids possesses the greatest strength?

Accepted Answer

Hydroiodic acid (HI)

Answer

Hydrochloric acid (HCl)

Answer

Hydrobromic acid (HBr)

Answer

Hydrofluoric acid (HF)

Question 38

What is the pH value of a neutral solution?

Accepted Answer

7

Answer

0

Answer

14

Answer

10

Question 39

Which of the following reactions is an example of a redox reaction?

Accepted Answer

Combustion of magnesium

Answer

Neutralization

Answer

Precipitation

Answer

Dissolution of salt in water

Question 40

In the reaction: Zn + 2HCl → ZnCl₂ + H₂, which species acts as the oxidizing agent?

Accepted Answer

Hydrochloric acid (HCl)

Answer

Zinc (Zn)

Answer

Zinc chloride (ZnCl₂)

Answer

Hydrogen gas (H₂)

Question 41

Which of the following gases contributes to the greenhouse effect?

Accepted Answer

Carbon dioxide

Answer

Oxygen

Answer

Nitrogen

Answer

Helium

Question 42

Which of the following is the conjugate acid of NH3?

Accepted Answer

NH4+

Answer

NH2-

Answer

H3O+

Answer

OH-

Question 43

Which of the following equations represents a redox reaction?

Accepted Answer

2Cu + O2 → 2CuO

Answer

NaOH + HCl → NaCl + H2O

Answer

NH3 + HNO3 → NH4NO3

Answer

CaCO3 → CaO + CO2

Question 44

Which of the following is a strong oxidizing agent?

Accepted Answer

KMnO4

Answer

Na

Answer

HCl

Answer

H2

Question 45

What is the product of the reaction between sodium hydroxide and nitric acid?

Accepted Answer

Sodium nitrate and water

Answer

Sodium chloride and water

Answer

Sodium hydrogen nitrate and water

Answer

Sodium bisnitrate and water

Question 46

What is the conjugate base of H3PO4?

Accepted Answer

PO43-

Answer

H2PO4-

Answer

H3O+

Answer

OH-

Question 47

Which of the following solutions can act as a buffer?

Accepted Answer

A mixture of acetic acid and sodium acetate

Answer

A mixture of hydrochloric acid and sodium chloride

Answer

A mixture of sodium hydroxide and potassium hydroxide

Answer

A mixture of water and ethanol

Question 48

When a small amount of a strong acid is added to a buffer solution, what happens to the pH?

Accepted Answer

The pH decreases because the strong acid consumes the weak base in the buffer solution.

Answer

The pH increases because the buffer solution neutralizes the strong acid.

Answer

The pH remains unchanged because buffer solutions resist pH changes.

Answer

The pH increases because the strong acid shifts the equilibrium of the buffer solution to the left.

Question 49

Which of the following is the conjugate acid of HSO3-?

Accepted Answer

H2SO3

Answer

SO3

Answer

OH-

Question 50

Which of the following is classified as a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Ethanoic acid

Question 51

What is the pH of a solution with a hydrogen ion concentration of 1 x 10^-7 mol/dm³?

Accepted Answer

7

Answer

0

Answer

14

Answer

1 x 10^-7

Question 52

Which of the following reactions is a redox reaction?

Accepted Answer

Combustion

Answer

Neutralisation

Answer

Precipitation

Answer

Hydrolysis

Question 53

In the reaction: Fe + 2HCl → FeCl₂ + H₂, which species is the oxidising agent?

Accepted Answer

HCl

Answer

Fe

Answer

FeCl₂

Answer

H₂

Question 54

What is the standard electrode potential of the standard hydrogen electrode?

Accepted Answer

0 V

Answer

1 V

Answer

–1 V

Answer

2 V

Question 55

Which of the following is the correct half-equation for the reduction of copper ions?

Accepted Answer

Cu²⁺ + 2 e⁻ → Cu

Answer

Cu → Cu²⁺ + 2 e⁻

Answer

Cu²⁺ + e⁻ → Cu⁺

Answer

Cu⁺ → Cu²⁺ + e⁻

Question 56

Explain the relationship between hydrogen ion (H+) concentration and pH. Why is the pH scale logarithmic?

Accepted Answer

H+ concentration is inversely proportional to pH, resulting in a logarithmic pH scale. A tenfold change in H+ concentration corresponds to a one-unit change in pH.

Answer

H+ concentration is directly proportional to pH, making the pH scale linear.

Answer

H+ concentration is not related to pH. The pH scale is arbitrary and has no mathematical relationship to H+ concentration.

Answer

The pH scale is linear because it represents the concentration of H+ ions in moles per liter.

Question 57

Which of the following is **strongest** acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Citric acid

Question 58

What is the pH of a **0.01** M solution of NaOH?

Accepted Answer

13

Answer

1

Answer

7

Answer

14

Question 59

Which of the following is a buffer solution?

Accepted Answer

A solution with equal concentrations of a weak acid and its conjugate base

Answer

A solution with a high concentration of H+ ions

Answer

A solution with a high concentration of OH- ions

Answer

A solution with a pH of 7

Question 60

What is the conjugate base of H2SO4?

Accepted Answer

SO42-

Answer

HSO4-

Answer

H3O+

Answer

OH-

Question 61

Which of the following is a Lewis acid?

Accepted Answer

BF3

Answer

NH3

Answer

NaOH

Answer

HCl

Question 62

What is the pH of a neutral solution at 25°C?

Accepted Answer

7

Answer

0

Answer

14

Answer

-7

Question 63

Which of the following is classified as a strong acid?

Accepted Answer

Hydrochloric acid (HCl)

Answer

Carbonic acid (H2CO3)

Answer

Acetic acid (CH3COOH)

Answer

Ammonia (NH3)

Question 64

Which of the following is a weak base?

Accepted Answer

Ammonia (NH3)

Answer

Calcium hydroxide (Ca(OH)2)

Answer

Sodium hydroxide (NaOH)

Answer

Potassium hydroxide (KOH)