Redox Reactions: Interactive Quizzes and Practice Questions

Question 1

Which of the following substances is NOT a product of oxidation?

Accepted Answer

Hydrogen

Answer

Oxygen

Answer

Water

Answer

Carbon dioxide

Question 2

Write the half-reaction for the reduction of copper(II) ions (Cu²⁺) to copper metal (Cu).

Accepted Answer

Cu²⁺ + 2 e^- → Cu

Answer

Cu → Cu²⁺ + 2 e^-

Answer

2 Cu²⁺ → Cu + Cu⁺

Answer

Cu⁺ → Cu²⁺ + e^-

Question 3

Which of the following electrochemical cells has the highest cell potential?

Accepted Answer

Al | Al³⁺ || Cu²⁺ | Cu

Answer

Zn | Zn²⁺ || Cu²⁺ | Cu

Answer

Fe | Fe²⁺ || Cu²⁺ | Cu

Answer

Mg | Mg²⁺ || Cu²⁺ | Cu

Question 4

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

Accepted Answer

To maintain electrical neutrality

Answer

To allow electron flow

Answer

To prevent solution mixing

Answer

To increase cell potential

Question 5

Which of the following is a reducing agent in a redox reaction?

Accepted Answer

Sodium (Na)

Answer

Potassium permanganate (KMnO₄)

Answer

Copper oxide (CuO)

Answer

Hydrochloric acid (HCl)

Question 6

In an electrochemical cell, the positively charged electrode is called the:

Accepted Answer

Anode

Answer

Cathode

Answer

Salt bridge

Answer

Electrolyte

Question 7

The standard hydrogen electrode (SHE) has an oxidation-reduction potential of:

Accepted Answer

0 V

Answer

1 V

Answer

-1 V

Answer

It varies depending on temperature

Question 8

The process of coating iron with zinc to prevent rusting is known as:

Accepted Answer

Galvanization

Answer

Electroplating

Answer

Anodizing

Answer

Cathodic protection

Question 9

Identify the balanced equation for the reaction between iron (Fe) and copper(II) sulfate (CuSO₄):

Accepted Answer

2Fe + 3CuSO₄ → Fe₂(SO₄)₃ + 3Cu

Answer

Fe + CuSO₄ → FeSO₄ + Cu

Answer

Fe + 2CuSO₄ → FeSO₄ + Cu₂SO₄

Answer

3Fe + 2CuSO₄ → Fe₃(SO₄)₂ + Cu

Question 10

Which process involves the loss of electrons, with the substance being oxidized?

Accepted Answer

Oxidation

Answer

Reduction

Answer

Electrolysis

Answer

Ionization

Question 11

In the reaction Fe + CuSO₄ → FeSO₄ + Cu, which species undergoes oxidation?

Accepted Answer

Fe

Answer

Cu

Answer

SO₄²⁻

Answer

Cu²⁺

Question 12

Which of the following is the half-reaction for the reduction of oxygen in an alkaline solution?

Accepted Answer

O₂ + 2H₂O + 4e⁻ → 4OH⁻

Answer

O₂ + 4H⁺ + 4e⁻ → 2H₂O

Answer

O₂ + 2e⁻ → 2O²⁻

Answer

O₂ + 4e⁻ → 4O²⁻

Question 13

Which of the following is NOT considered an oxidizing agent?

Accepted Answer

Zn

Answer

KMnO₄

Answer

H₂O₂

Answer

Fe³⁺

Question 14

In the reaction Fe + 2HCl → FeCl2 + H2, which species undergoes oxidation?

Accepted Answer

Fe

Answer

HCl

Answer

FeCl2

Answer

H2

Question 15

What is the standard electrode potential (E°) of a hydrogen electrode?

Accepted Answer

0.00 V

Answer

1.00 V

Answer

2.00 V

Answer

3.00 V

Question 16

In the electrochemical cell Zn | Zn2+(1M) || Cu2+(1M) | Cu, which electrode is the cathode?

Accepted Answer

Cu electrode

Answer

Zn electrode

Answer

Zn2+ solution

Answer

Cu2+ solution

Question 17

What are the products of the electrolysis of water?

Accepted Answer

Hydrogen and oxygen

Answer

Sodium and chlorine

Answer

Copper and silver

Answer

Gold and platinum

Question 18

Which of the following is a redox titration?

Accepted Answer

Titration of KMnO4 with Fe2+

Answer

Titration of HCl with NaOH

Answer

Titration of H2SO4 with Ba(OH)2

Answer

Titration of CH3COOH with NaOH

Question 19

In a redox reaction, which process involves the loss of electrons?

Accepted Answer

Oxidation

Answer

Reduction

Answer

Ionization

Answer

Neutralization

Question 20

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

Accepted Answer

To connect the two half-cells and allow ion flow

Answer

To generate an electric current

Answer

To prevent mixing of solutions

Answer

To act as a catalyst

Question 21

Which of the following is a characteristic of a spontaneous redox reaction?

Accepted Answer

Positive cell potential

Answer

Negative cell potential

Answer

Requires external energy input

Answer

Produces no electrical energy

Question 22

Which metal has the highest reduction potential?

Accepted Answer

Gold

Answer

Sodium

Answer

Iron

Answer

Copper

Question 23

What is the primary application of electrolysis in industry?

Accepted Answer

Extraction of metals from ores

Answer

Electroplating

Answer

Water purification

Answer

Generation of fuels

Question 24

Which of the following reactions is a redox reaction?

Accepted Answer

2H2 + O2 → 2H2O

Answer

NaOH + HCl → NaCl + H2O

Answer

CaCO3 → CaO + CO2

Answer

NH3 + HCl → NH4Cl

Question 25

What is the purpose of a redox indicator in a titration?

Accepted Answer

To indicate the endpoint of the reaction by changing color

Answer

To measure the pH of the solution

Answer

To act as a catalyst

Answer

To generate an electric current

Question 26

What is the standard hydrogen electrode (SHE), and why is it crucial in determining electrode potentials?

Accepted Answer

The SHE is a hydrogen gas electrode immersed in a 1 atm hydrogen gas atmosphere, assigned a potential of 0 V under standard conditions, serving as a reference point for electrode potentials.

Answer

The SHE measures the potential difference between two electrodes within an electrochemical cell.

Answer

The SHE functions solely as the cathode in electrochemical cells.

Answer

The SHE can only be utilized in acidic environments.

Question 27

How do redox reactions contribute to the essential life processes of plants and animals?

Accepted Answer

Redox reactions provide energy for cellular processes like respiration and photosynthesis.

Accepted Answer

Redox reactions regulate metabolic pathways by controlling enzyme activity and signaling molecules.

Accepted Answer

Redox reactions are essential for synthesizing essential molecules like carbohydrates and proteins for growth and repair.

Answer

Redox reactions play no significant role in biological systems.

Question 28

Which of the following definitions of oxidation is correct?

Accepted Answer

Loss of electrons

Answer

Loss of protons

Answer

Gain of electrons

Answer

Gain of protons

Question 29

Which of the following is a common use of electrochemical cells?

Accepted Answer

Batteries

Answer

Light bulbs

Answer

Solar panels

Answer

Electric motors

Question 30

What is the balanced equation for the reaction between potassium permanganate (KMnO₄) and oxalic acid (H₂C₂O₄)?

Accepted Answer

2KMnO₄ + 5H₂C₂O₄ + 8H₂SO₄ → K₂SO₄ + 2MnSO₄ + 10CO₂ + 8H₂O

Answer

2KMnO₄ + 3H₂C₂O₄ + 4H₂SO₄ → 2MnSO₄ + K₂SO₄ + 6CO₂ + 5H₂O

Answer

KMnO₄ + H₂C₂O₄ + H₂SO₄ → MnO₂ + CO₂ + H₂O

Question 31

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

Accepted Answer

To maintain electrical neutrality

Answer

To allow electron flow

Answer

To prevent mixing of solutions

Answer

To increase the cell potential

Question 32

In the reaction Fe + CuSO₄ → Cu + FeSO₄, identify the species undergoing oxidation:

Accepted Answer

Fe

Answer

Fe²⁺

Answer

SO₄²⁻

Answer

Cu

Question 33

Which process involves the conversion of a metal oxide into a metal and is endothermic in nature?

Accepted Answer

Reduction

Answer

Electrolysis

Answer

Corrosion

Answer

Oxidation

Question 34

In the Daniell cell, the reaction occurring at the cathode is:

Accepted Answer

Cu²⁺ + 2 e⁻ → Cu

Answer

Zn → Zn²⁺ + 2 e⁻

Answer

SO₄²⁻ → SO₃²⁻ + 2 e⁻

Answer

Fe³⁺ + e⁻ → Fe²⁺

Question 35

In the reaction 2 PbO + C → 2 Pb + CO₂, identify the reducing agent:

Accepted Answer

C

Answer

Pb

Answer

CO₂

Answer

O₂

Question 36

Determine the oxidation state of nitrogen in HNO₃:

Accepted Answer

+5

Answer

+4

Answer

-3

Answer

+3

Question 37

Identify the reaction that is not a redox reaction:

Accepted Answer

HCl + NaOH → NaCl + H₂O

Answer

CuO + H₂ → Cu + H₂O

Answer

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

Answer

2 Na + 2 H₂O → 2 NaOH + H₂

Question 38

Electroplating involves the:

Accepted Answer

Reduction of metal ions at the cathode

Answer

Electrolysis of water to produce hydrogen and oxygen

Answer

Formation of a non-metallic coating on a metal surface

Answer

Oxidation of metal ions at the anode

Question 39

Balance the following redox reaction: KMnO4 + HCl → Cl2 + MnCl2 + KCl + H2O

Accepted Answer

2KMnO4 + 16HCl → 2Cl2 + 2MnCl2 + 2KCl + 8H2O

Answer

KMnO4 + 2HCl → Cl2 + MnCl2 + KCl + 2H2O

Answer

2KMnO4 + 10HCl → 4Cl2 + 2MnCl2 + 2KCl + 8H2O

Answer

KMnO4 + 8HCl → Cl2 + MnCl2 + KCl + 4H2O

Question 40

In an electrochemical cell, which electrode is where oxidation occurs?

Accepted Answer

Anode

Answer

Cathode

Answer

Electrolyte

Answer

Salt bridge

Question 41

Identify the oxidizing agent in the reaction: Sn2+ + 2Fe3+ → Sn4+ + 2Fe2+

Accepted Answer

Fe3+

Answer

Sn2+

Answer

Sn4+

Answer

Fe2+

Question 42

Which of the following is an example of a redox reaction in everyday life?

Accepted Answer

Rusting of iron

Answer

Dissolving of salt in water

Answer

Combustion of wood

Answer

Neutralization of an acid and a base

Question 43

What is the standard reduction potential of the hydrogen electrode?

Accepted Answer

0 V

Answer

1 V

Answer

-1 V

Question 44

Which of the following is a limitation of using redox reactions in batteries?

Accepted Answer

Eventual depletion of reactants

Answer

Reversibility of reactions

Answer

Long shelf life

Answer

High efficiency of energy conversion

Question 45

Identify the type of redox reaction where the same species undergoes both oxidation and reduction:

Accepted Answer

Disproportionation

Answer

Displacement

Answer

Decomposition

Answer

Combination