Redox Reactions: Learn and Master the Basics of Oxidation-Reduction

Question 1

What is the oxidizing agent in the reaction: Fe + CuSO4 → FeSO4 + Cu?

Accepted Answer

CuSO4

Answer

Fe

Answer

FeSO4

Answer

Cu

Question 2

Which of the following statements about redox reactions is FALSE?

Accepted Answer

The oxidizing agent is the species that is oxidized.

Answer

Oxidation and reduction must occur simultaneously.

Answer

Redox reactions can be used to generate electricity.

Answer

Redox reactions can be used to protect metals from corrosion.

Question 3

How do redox reactions facilitate energy production in cellular respiration?

Accepted Answer

Electron transfer in the electron transport chain

Answer

Glucose breakdown

Answer

Oxygen consumption

Question 4

A galvanic cell is a device that converts:

Accepted Answer

Chemical energy into electrical energy

Answer

Electrical energy into chemical energy

Answer

Heat energy into electrical energy

Answer

Light energy into electrical energy

Question 5

The standard reduction potential of a half-reaction indicates the:

Accepted Answer

Tendency of a species to be reduced

Answer

Tendency of a species to be oxidized

Answer

Rate of the reaction

Answer

Equilibrium constant of the reaction

Question 6

Which factor does NOT affect the efficiency of a fuel cell?

Accepted Answer

Volume of the cell

Answer

Concentration of reactants

Answer

Temperature

Answer

Surface area of electrodes

Question 7

A battery is a device that:

Accepted Answer

Stores chemical energy and converts it to electrical energy

Answer

Stores electrical energy and converts it to chemical energy

Answer

Generates electricity from mechanical energy

Answer

Converts heat energy into electrical energy

Question 8

What is a defining characteristic of redox reactions?

Accepted Answer

Electron exchange between atoms or ions

Answer

Occur only in water-based solutions

Answer

Always release heat

Answer

Have no practical applications

Question 9

In the reaction: Zn + Cu²⁺ → Zn²⁺ + Cu, which species is the oxidizing agent?

Accepted Answer

Cu²⁺

Answer

Zn

Answer

Cu

Answer

Zn²⁺

Question 10

What is the half-reaction for the reduction of oxygen?

Accepted Answer

½ O₂ + 2H⁺ + 2e⁻ → H₂O

Answer

H₂O → ½ O₂ + 2H⁺ + 2e⁻

Answer

O₂ + H₂O + 2e⁻ → 2OH⁻

Answer

2OH⁻ → O₂ + H₂O + 2e⁻

Question 11

In a galvanic cell, the electrode where oxidation occurs is called the:

Accepted Answer

Anode

Answer

Positive electrode

Answer

Negative electrode

Answer

Cathode

Question 12

Which of the following is an example of a disproportionation reaction?

Accepted Answer

Cl₂ + 2OH⁻ → ClO⁻ + Cl⁻ + H₂O

Answer

H₂O → ½ O₂ + 2H⁺ + 2e⁻

Answer

Fe + 2HCl → FeCl₂ + H₂

Answer

CuSO₄ + 2NaOH → Cu(OH)₂ + Na₂SO₄

Question 13

In the reaction: 2Na + 2HCl → 2NaCl + H₂, which species undergoes oxidation?

Accepted Answer

Na

Answer

HCl

Answer

NaCl

Answer

H₂

Question 14

In the reaction between zinc and copper(II) sulfate, which species undergoes oxidation?

Accepted Answer

Zinc

Answer

Copper

Answer

Sulfate ions

Answer

Water

Question 15

Which of the following is a common reducing agent in redox reactions?

Accepted Answer

Sodium

Answer

Potassium permanganate

Answer

Iron(III) ions

Answer

Chloride ions

Question 16

The half-reaction representing the oxidation of water is:

Accepted Answer

2H2O → O2 + 4H+ + 4e-

Answer

H2O + 2e- → H2 + OH-

Answer

2H+ + 2e- → H2

Answer

O2 + 4H+ + 4e- → 2H2O

Question 17

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

Accepted Answer

Pressure

Answer

Concentration of reactants

Answer

Temperature

Answer

Presence of a catalyst

Question 18

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

Accepted Answer

Always produce a visible color change

Answer

Involve the transfer of electrons

Answer

Include both oxidation and reduction processes

Answer

Can be used to generate electrical energy

Question 19

In the reaction: Fe + CuSO₄ → FeSO₄ + Cu, which species is oxidized?

Accepted Answer

Fe

Answer

Cu

Answer

SO<sub>4</sub>

Answer

FeSO<sub>4</sub>

Question 20

What is the role of a catalyst in a redox reaction?

Accepted Answer

To lower the activation energy of the reaction

Answer

To increase the activation energy of the reaction

Answer

To change the products of the reaction

Answer

To prevent the reaction from occurring

Question 21

Which type of titration involves the reaction of an oxidizing agent with a reducing agent?

Accepted Answer

Redox titration

Answer

Acid-base titration

Answer

Iodometric titration

Answer

Complexometric titration

Question 22

Which of the following is **not** a characteristic of redox reactions?

Accepted Answer

Breaking of chemical bonds

Answer

Transfer of electrons

Answer

Change in oxidation number of atoms

Answer

Release or absorption of energy

Question 23

In the reaction: Fe₂O₃ + 3CO → 2Fe + 3CO₂, which species is being **oxidized**?

Accepted Answer

Fe₂O₃

Answer

CO

Answer

Fe

Answer

CO₂

Question 24

The half-reaction for the **reduction** of Fe³⁺ to Fe²⁺ is:

Accepted Answer

Fe³⁺ + e⁻ → Fe²⁺

Answer

Fe²⁺ + e⁻ → Fe³⁺

Answer

Fe³⁺ + 2e⁻ → Fe²⁺

Answer

Fe²⁺ + 3e⁻ → Fe³⁺

Question 25

The **cathode** in a galvanic cell is the electrode where:

Accepted Answer

Reduction occurs

Answer

Oxidation occurs

Answer

Electrons are released

Answer

Electrons are gained

Question 26

Which of the following is NOT a defining characteristic of a redox reaction?

Accepted Answer

Formation of a colored solution

Answer

Transfer of electrons

Answer

Change in oxidation state

Answer

Release of heat

Question 27

In the balanced equation below, which species is oxidized?
2Fe + 3Cl₂ -> 2FeCl₃

Accepted Answer

Fe

Answer

Cl₂

Answer

FeCl₃

Answer

Neither Fe nor Cl₂

Question 28

A hydrogen fuel cell generates electricity by utilizing a chemical reaction. Which of the following statements about this reaction is correct?

Accepted Answer

Hydrogen undergoes oxidation, while oxygen undergoes reduction.

Answer

Oxygen undergoes oxidation, while hydrogen undergoes reduction.

Answer

Both hydrogen and oxygen undergo oxidation.

Answer

Both hydrogen and oxygen undergo reduction.

Question 29

Which of the following species can act as a reducing agent?

Accepted Answer

Zn

Answer

MnO₄⁻

Answer

Cl⁻

Answer

Fe³⁺

Question 30

Which of the following factors does NOT influence the rate of a redox reaction?

Accepted Answer

Type of solvent used

Answer

Concentration of reactants

Answer

Temperature

Answer

Presence of a catalyst

Question 31

What is a concise definition of oxidation?

Accepted Answer

Loss of electrons

Answer

Loss of protons

Answer

Gain of electrons

Question 32

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

Accepted Answer

Fe

Answer

FeCl2

Answer

H2

Answer

HCl

Question 33

Which of the following substances can act as a reducing agent?

Accepted Answer

Zn

Answer

Cl-

Answer

Fe3+

Answer

Cu2+

Question 34

In an electrochemical cell, reduction takes place at the:

Accepted Answer

Cathode

Answer

Anode

Answer

Salt bridge

Question 35

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

Accepted Answer

Rusting of iron

Answer

Dissolving sugar in water

Answer

Melting of ice

Answer

Evaporation of water

Question 36

Which of the following reactions involves the transfer of electrons, indicating a redox reaction?

Accepted Answer

Fe2+ + 2e- → Fe

Answer

CaCO3 → CaO + CO2

Answer

HCl + NaOH → NaCl + H2O

Answer

C6H12O6 → 2C2H5OH + 2CO2

Question 37

If the standard electrode potential of a half-cell is positive, it indicates that:

Accepted Answer

The half-reaction is a reduction

Answer

The half-reaction involves a metal

Answer

The half-reaction involves a non-metal

Question 38

Which of the following is the strongest oxidizing agent?

Accepted Answer

F2

Answer

Cl2

Answer

Br2

Question 39

In a galvanic cell, what is the nature of the overall cell reaction?

Accepted Answer

Spontaneous and generates electricity

Answer

Non-spontaneous and generates electricity

Answer

Spontaneous and consumes electricity

Question 40

Which of the following situations represents a redox reaction?

Accepted Answer

The reaction between zinc and sulfuric acid

Answer

The mixing of ethanol and water

Answer

The melting of water

Answer

The sublimation of iodine

Question 41

In the reaction 2Na + Cl2 → 2NaCl, identify the oxidizing and reducing agents.

Accepted Answer

Cl is the oxidizing agent, reducing Na

Answer

Na is the oxidizing agent, reducing Cl

Answer

Cl is the reducing agent, oxidizing Na

Question 42

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

Accepted Answer

Zn

Answer

H2

Answer

HCl

Answer

ZnCl2

Question 43

Consider the half-reactions:
1. Fe2+ → Fe3+ + e−
2. Cu+ + e− → Cu

Which of the following is the correct overall redox reaction?

Accepted Answer

Fe2+ + Cu+ → Fe3+ + Cu

Answer

Fe3+ + Cu → Fe2+ + Cu2+

Answer

Fe2+ + Cu → Fe3+ + Cu2+

Answer

Fe3+ + Cu+ → Fe2+ + Cu

Question 44

Which of the following is an example of a redox titration?

Accepted Answer

Titration of potassium permanganate against oxalic acid

Answer

Titration of sodium hydroxide against hydrochloric acid

Answer

Titration of silver nitrate against sodium chloride

Question 45

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

Accepted Answer

The oxidation number of all elements remains constant

Answer

Oxidation and reduction occur simultaneously

Answer

Electrons are transferred between species

Question 46

In the reaction: Zn + 2HCl → ZnCl2 + H2, which species is oxidized?

Accepted Answer

Zn

Answer

ZnCl2

Answer

HCl

Answer

H2

Question 47

Which of the following is a strong reducing agent?

Accepted Answer

Li

Answer

F2

Answer

H2SO4

Answer

MnO4-

Question 48

In an electrochemical cell, where does reduction occur?

Accepted Answer

Cathode

Answer

Salt bridge

Answer

Electrolyte

Answer

Anode

Question 49

What is the reducing agent in the following reaction: 2Fe3+ + 2I- → 2Fe2+ + I2?

Accepted Answer

I-

Answer

Fe2+

Answer

Fe3+

Answer

I2

Question 50

Which of the following is a balanced redox reaction equation?

Accepted Answer

2Cu + O2 → 2CuO

Answer

Cu + O2 → CuO

Answer

2Cu + 2O2 → Cu2O3

Answer

Cu + 2O2 → CuO2