Redox Reactions: A Comprehensive Guide for Year 13 Chemistry Students

Question 1

Identify the species oxidized in the reaction: Fe2+ → Fe3+ + e-

Accepted Answer

Fe2+

Answer

Fe3+

Answer

e-

Question 2

Consider the following cell reaction: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s). Which electrode is the cathode?

Accepted Answer

Cu electrode

Answer

Zn electrode

Question 3

Which of the following factors does not affect the rate of a redox reaction?

Accepted Answer

Type of salt bridge used

Answer

Concentration of reactants

Answer

Temperature

Answer

Surface area of reactants

Question 4

What is the oxidation state of nitrogen in NO3-?

Accepted Answer

+5

Answer

-3

Answer

-2

Answer

+3

Question 5

Identify the reducing agent in the reaction: 2KMnO4 + 5SO2 + 2H2O → K2SO4 + 2MnSO4 + 2H2SO4

Accepted Answer

SO2

Answer

KMnO4

Answer

MnSO4

Answer

H2SO4

Question 6

Which of the following is a single displacement reaction?

Accepted Answer

2Na + 2H2O → 2NaOH + H2

Answer

2FeCl3 + 3Na2CO3 → Fe2(CO3)3 + 6NaCl

Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

2NH3 + 3Cl2 → N2 + 6HCl

Question 7

What is the main purpose of a salt bridge in an electrochemical cell?

Accepted Answer

To complete the electrical circuit

Answer

To allow electrons to flow between the half-cells

Answer

To prevent the mixing of solutions

Answer

To increase the rate of the reaction

Question 8

In the redox reaction between copper metal and silver nitrate, what half-reaction occurs at the anode?

Accepted Answer

Cu → Cu2+ + 2e-

Answer

Ag+ + e- → Ag

Answer

2Ag+ + 2e- → 2Ag

Answer

Cu2+ + 2e- → Cu

Question 9

In an electrochemical cell, the electrode where electrons are produced is known as the:

Accepted Answer

Anode

Answer

Cathode

Answer

Electrolyte

Answer

Salt bridge

Question 10

Which of the following reactions is a displacement reaction?

Accepted Answer

Zn + CuSO4 → ZnSO4 + Cu

Answer

2H2 + O2 → 2H2O

Answer

2Na + 2H2O → 2NaOH + H2

Answer

Fe2O3 + 3CO → 2Fe + 3CO2

Question 11

What is the primary role of the salt bridge in an electrochemical cell?

Accepted Answer

To maintain electrical neutrality in the cell

Answer

To allow electrons to flow between the electrodes

Answer

To prevent mixing of the solutions

Answer

To increase the conductivity of the solution

Question 12

Which of the following energy sources is classified as a primary cell?

Accepted Answer

Dry cell

Answer

Lead-acid battery

Answer

Fuel cell

Answer

Lithium-ion battery

Question 13

What is the standard reduction potential of the hydrogen electrode?

Accepted Answer

0.00 V

Answer

1.00 V

Answer

-1.00 V

Answer

2.00 V

Question 14

In an electrochemical cell, the half-reaction taking place at the anode is:

Accepted Answer

Oxidation

Answer

Reduction

Question 15

The standard reduction potential of the H⁺/H₂ couple is 0 V. This implies that:

Accepted Answer

Hydrogen is neither a good reducing nor oxidizing agent.

Answer

Hydrogen is a very strong reducing agent.

Answer

Hydrogen is a very strong oxidizing agent.

Question 16

How do redox reactions impact the environment, considering their role in pollution and sustainability?

Accepted Answer

Redox reactions can contribute to air pollution by releasing harmful gases like carbon dioxide and nitrogen oxides.

Answer

Redox reactions have no significant environmental impact and are only relevant to industrial processes.

Answer

Electrochemical cells have no environmental benefits and are used solely for electricity generation.

Answer

Redox reactions do not contribute to water pollution or the degradation of aquatic ecosystems.

Question 17

In the redox reaction below, which species is the oxidizing agent?

4Fe^(2+) + O2 + 4H^+ -> 4Fe^(3+) + 2H2O

Accepted Answer

O2

Answer

Fe^(2+)

Answer

H^+

Answer

Fe^(3+)

Question 18

In the reaction: 2Fe + 3Cl2 -> 2FeCl3, which substance undergoes oxidation?

Accepted Answer

Fe

Answer

Cl2

Answer

FeCl3

Answer

Neither Fe nor Cl2

Question 19

Which statement accurately describes the Faraday constant?

Accepted Answer

It represents the charge carried by one mole of electrons.

Answer

It is equivalent to the molar mass of an electron.

Answer

It measures the efficiency of electrochemical cells.

Answer

It is used to compute the number of electrons transferred in a redox reaction.

Question 20

What is the oxidation state of nitrogen in HNO3?

Accepted Answer

+5

Answer

+1

Answer

+3

Answer

-3

Question 21

Identify the oxidizing agent in the following reaction:

Accepted Answer

MnO4-

Answer

Fe2+

Answer

I2

Answer

H2

Question 22

Which of the following is not a type of redox reaction?

Accepted Answer

Neutralization

Answer

Combustion

Answer

Displacement

Answer

Electrolysis

Question 23

Which of the following is a strong oxidizing agent?

Accepted Answer

MnO4-

Answer

Na+

Answer

Cl-

Answer

Fe2+

Question 24

In the half-reaction: Fe²⁺ → Fe³⁺ + e^-, the species Fe²⁺ acts as the:

Accepted Answer

Reductant

Answer

Oxidant

Answer

Electrode

Answer

Catalyst

Question 25

In an electrochemical cell, oxidation occurs at the:

Accepted Answer

Anode

Answer

Cathode

Answer

Salt bridge

Answer

External circuit

Question 26

A voltaic cell converts:

Accepted Answer

Chemical energy to electrical energy

Answer

Electrical energy to chemical energy

Answer

Light energy to chemical energy

Answer

Sound energy to electrical energy

Question 27

Which of the following is NOT a characteristic of redox reactions?

Accepted Answer

Always cause an increase in temperature

Answer

Involve the transfer of electrons

Answer

Produce a change in oxidation state

Answer

Can be used to generate electricity

Question 28

Which of the following is the half-reaction for the reduction of oxygen in the following reaction: 2H2O + O2 → 4H+ + 4e-

Accepted Answer

O2 + 4H+ + 4e- → 2H2O

Answer

2H2O → O2 + 4H+ + 4e-

Answer

2H+ + 2e- → H2

Answer

O2 → 2O2-

Question 29

What is the oxidation number of nitrogen in the compound NH4NO3?

Accepted Answer

+5

Answer

-3

Answer

0

Answer

+3

Question 30

Which of the following is a reducing agent?

Accepted Answer

Fe2+

Answer

MnO4-

Answer

Br2

Answer

Cu2+

Question 31

In an electrochemical cell, the reaction at the positive electrode is:

Accepted Answer

Oxidation

Answer

Reduction

Answer

Electron flow

Answer

Ion exchange

Question 32

The following reaction is an example of a:

Accepted Answer

Redox reaction

Answer

Combustion reaction

Answer

Decomposition reaction

Answer

Neutralization reaction

Question 33

Which of the following is the half-reaction for the oxidation of water?

Accepted Answer

H2O → 1/2O2 + 2H+ + 2e-

Answer

1/2O2 + 2H+ + 2e- → H2O

Answer

2H2O → O2 + 4H+ + 4e-

Answer

O2 + 4H+ + 4e- → 2H2O

Question 34

What is the oxidation state of iron in Fe2O3?

Accepted Answer

+3

Answer

+1

Answer

+2

Answer

+4

Question 35

In the electrolysis of water, which electrode is the cathode?

Accepted Answer

Hydrogen electrode

Answer

Carbon electrode

Answer

Graphite electrode

Answer

Oxygen electrode

Question 36

Which of the following is a strong electrolyte?

Accepted Answer

Sodium chloride (NaCl)

Answer

Water (H2O)

Answer

Carbon dioxide (CO2)

Answer

Glucose (C6H12O6)

Question 37

Which of the following is a weak acid?

Accepted Answer

Acetic acid (CH3COOH)

Answer

Hydrochloric acid (HCl)

Answer

Nitric acid (HNO3)

Answer

Sulfuric acid (H2SO4)

Question 38

Define an oxidizing agent.

Accepted Answer

A substance that causes another substance to lose electrons

Answer

A substance that causes another substance to gain electrons

Answer

A substance that causes another substance to lose protons

Answer

A substance that causes another substance to gain protons

Question 39

In the reaction: Fe + CuSO4 -> FeSO4 + Cu, identify the species undergoing reduction.

Accepted Answer

Cu

Answer

Fe

Answer

SO42-

Answer

CuSO4

Question 40

What factor does NOT affect the EMF of an electrochemical cell?

Accepted Answer

Pressure

Answer

Concentration of reactants

Answer

Temperature

Answer

Nature of electrodes

Question 41

In the electroplating of silver onto a spoon, silver ions (Ag+) are:

Accepted Answer

Reduced

Answer

Oxidized

Answer

Neither oxidized nor reduced

Answer

Both oxidized and reduced

Question 42

Which of the following species is a reducing agent?

Accepted Answer

Fe2+

Answer

Fe3+

Answer

Cu2+

Answer

MnO4-

Question 43

The half-reaction representing the reduction of iron(III) to iron(II) is:

Accepted Answer

Fe3+ + e- → Fe2+

Answer

Fe2+ + e- → Fe3+

Answer

Fe3+ → Fe2+ + e-

Answer

Fe2+ → Fe3+ + e-

Question 44

A voltaic cell generates:

Accepted Answer

Electrical energy from chemical energy

Answer

Chemical energy from electrical energy

Answer

Electrical energy from light energy

Answer

Light energy from electrical energy

Question 45

The emf of a cell measures the:

Accepted Answer

Maximum electrical work obtainable from the cell

Answer

Equilibrium constant for the cell reaction

Answer

Rate of the cell reaction

Answer

Concentration of reactants in the cell

Question 46

Which of the following is NOT an application of electrochemical cells?

Accepted Answer

Solar panels

Answer

Fuel cells

Answer

Electroplating

Answer

Batteries

Question 47

In the reaction Fe + 2HCl → FeCl2 + H2, the species that undergoes oxidation is:

Accepted Answer

Fe

Answer

HCl

Answer

FeCl2

Answer

H2

Question 48

The half-reaction for the reduction of Cu2+ ions is:

Accepted Answer

Cu2+ + 2e- → Cu

Answer

Cu2+ → Cu + 2e-

Answer

2Cu2+ + 2e- → Cu

Answer

Cu → Cu2+ + 2e-

Question 49

In a galvanic cell, what is the primary function of the salt bridge?

Accepted Answer

Provide a supply of ions to maintain electrical neutrality

Answer

Prevent the mixing of solutions

Answer

Enable the flow of electrons

Answer

Enhance the voltage of the cell