Redox Reactions: Master Oxidation, Reduction, and Electrochemistry

Question 1

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

Accepted Answer

To facilitate ion movement

Answer

To enable electron flow between electrodes

Answer

To complete the electrical circuit

Answer

To prevent solution mixing

Question 2

Which species acts as a reducing agent?

Accepted Answer

Na

Answer

MnO2

Answer

KMnO4

Answer

Cl-

Question 3

What is the definition of the standard reduction potential of a half-reaction?

Accepted Answer

Potential difference between standard hydrogen electrode and the electrode of the half-reaction

Answer

Potential difference between anode and cathode

Answer

Potential difference between the two electrodes

Answer

Potential difference between electrolyte and electrode

Question 4

Within an electrochemical cell, what is the function of the cathode?

Accepted Answer

Electron receiver

Answer

Electron supplier

Answer

Equivalent to the anode

Answer

Circuit completion

Question 5

The main components of an electrochemical cell include:

Accepted Answer

Two electrodes immersed in an electrolyte solution

Answer

A battery and a resistor

Answer

A voltmeter and an ammeter

Answer

A power source and a load

Question 6

Electrolysis is a process that:

Accepted Answer

Uses electricity to drive a chemical reaction

Answer

Only occurs in aqueous solutions

Answer

Always produces a pure product

Answer

Is never used in industrial processes

Question 7

The standard reduction potential of a hydrogen electrode under standard conditions is:

Accepted Answer

0 V

Answer

1 V

Answer

−1 V

Answer

2 V

Question 8

Define oxidation clearly.

Accepted Answer

Loss of electrons

Answer

Loss of protons

Answer

Gain of electrons

Answer

Gain of protons

Question 9

Distinguish between electrolytic and galvanic cells.

Accepted Answer

Electrolytic cells use electrical energy to drive a chemical reaction, while galvanic cells generate electrical energy from a chemical reaction.

Answer

Galvanic cells use electrical energy to drive a chemical reaction, while electrolytic cells generate electrical energy from a chemical reaction.

Answer

Both electrolytic and galvanic cells use electrical energy to drive a chemical reaction.

Answer

Electrolytic cells are more efficient than galvanic cells.

Question 10

In the reaction Fe2+ → Fe3+, which species undergoes oxidation?

Accepted Answer

Fe2+

Answer

Fe3+

Answer

Both Fe2+ and Fe3+

Answer

Neither Fe2+ nor Fe3+

Question 11

Within an electrochemical cell, at which electrode does oxidation occur?

Accepted Answer

Anode

Answer

Cathode

Answer

Both anode and cathode

Answer

Neither anode nor cathode

Question 12

What term describes the process of utilizing an electric current to drive a non-spontaneous chemical reaction?

Accepted Answer

Electrolysis

Answer

Oxidation

Answer

Reduction

Answer

Electrophoresis

Question 13

Identify the reaction that exemplifies a redox reaction:

Accepted Answer

2Na + Cl2 → 2NaCl

Answer

CaCO3 → CaO + CO2

Answer

NaOH + HCl → NaCl + H2O

Answer

NH3 + HCl → NH4Cl

Question 14

Which factor does NOT influence the rate of an electrochemical reaction?

Accepted Answer

Volume of the electrochemical cell

Answer

Temperature

Answer

Concentration of reactants

Answer

Type of electrode material

Question 15

In the half-reaction Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O, which species serves as the oxidizing agent?

Accepted Answer

Cr2O72-

Answer

H+

Answer

e-

Answer

Cr3+

Question 16

Select the correct half-reaction for the reduction of MnO4- to Mn2+.

Accepted Answer

MnO4- + 8H+ + 5e- → Mn2+ + 4H2O

Answer

MnO4- + 2H+ + 2e- → Mn2+ + H2O

Answer

MnO4- + 4H+ + 4e- → Mn2+ + 2H2O

Answer

MnO4- + 6H+ + 3e- → Mn2+ + 3H2O

Question 17

What is the primary product of water electrolysis?

Accepted Answer

Hydrogen and oxygen

Answer

Hydrogen and chlorine

Answer

Oxygen and chlorine

Answer

Hydrogen and ozone

Question 18

What primarily determines a redox reaction's spontaneity?

Accepted Answer

Gibbs free energy change

Answer

Standard cell potential

Answer

Enthalpy change

Answer

Entropy change

Question 19

In the reaction: Cu + 2Ag+ → Cu2+ + 2Ag, which species is oxidized?

Accepted Answer

Cu

Answer

Ag+

Answer

Cu2+

Answer

Ag

Question 20

Which of the following applications involves electrolysis?

Accepted Answer

Electroplating

Answer

Batteries

Answer

Fuel cells

Answer

Corrosion

Question 21

The Haber process is an example of a:

Accepted Answer

Redox reaction

Answer

Combustion reaction

Answer

Neutralization reaction

Answer

Electrolysis reaction

Question 22

In an electrochemical cell, oxidation occurs at the:

Accepted Answer

Anode

Answer

Cathode

Answer

Salt bridge

Answer

External circuit

Question 23

Which species acts as a reducing agent?

Accepted Answer

Fe2+

Answer

MnO4-

Answer

Cr2O72-

Answer

Cl2

Question 24

What is the process called when electrical energy is converted into chemical energy?

Accepted Answer

Electrolysis

Answer

Oxidation

Answer

Reduction

Answer

Combustion

Question 25

During the electrolysis of molten sodium chloride, what is the product formed at the cathode?

Accepted Answer

Sodium

Answer

Chlorine

Answer

Hydrogen

Answer

Oxygen

Question 26

Which of the following is NOT a redox reaction?

Accepted Answer

Polymerization

Answer

Neutralization

Answer

Precipitation

Answer

Combustion

Question 27

Which of the following is a characteristic of redox reactions?

Accepted Answer

They involve the transfer of electrons between chemical species.

Answer

They occur exclusively in single-phase systems.

Answer

They are never utilized in batteries.

Answer

They cannot be used to generate electricity.

Question 28

In the reaction 2Fe + 3Cl2 → 2FeCl3, which substance undergoes oxidation?

Accepted Answer

Fe

Answer

Cl2

Answer

FeCl3

Answer

Neither Fe nor Cl2

Question 29

During electrolysis, oxidation takes place at which electrode?

Accepted Answer

Anode

Answer

Neither the anode nor the cathode

Answer

Salt bridge

Answer

Cathode

Question 30

Which of the following species acts as a reducing agent?

Accepted Answer

Sn2+

Answer

Fe3+

Answer

Ag+

Answer

Cu2+

Question 31

In the reaction:

2KMnO4 + 16HCl → 2MnCl2 + 2KCl + 8H2O + 5Cl2

How many moles of electrons are transferred per mole of KMnO4?

Accepted Answer

5

Answer

2

Answer

3

Answer

1

Question 32

Which of the following reactions is a disproportionation reaction?

Accepted Answer

2Cu+ → Cu + Cu2+

Answer

Cu + 2Ag+ → Cu2+ + 2Ag

Answer

Fe2+ + MnO4- + H+ → Fe3+ + Mn2+ + H2O

Answer

2H2O → O2 + 4H+ + 4e-

Question 33

Which of the following equations represents an oxidation reaction? Consider the concept of electron loss.

Accepted Answer

Fe(s) → Fe²⁺(aq) + 2 e⁻

Answer

2 H₂O₂(l) → 2 H₂O(l) + O₂(g)

Answer

2 Na(s) + Cl₂(g) → 2 NaCl(s)

Answer

Mg²⁺(aq) + 2 e⁻ → Mg(s)

Question 34

In the following reaction: Cu²⁺(aq) + Fe(s) → Cu(s) + Fe²⁺(aq), what is the reducing agent?

Accepted Answer

Fe

Answer

Fe²⁺

Answer

Cu²⁺

Answer

Cu

Question 35

Which of the following statements about electrochemical cells is accurate?

Accepted Answer

Electrochemical cells convert chemical energy into electrical energy.

Answer

Electrochemical cells require an external power source to operate.

Answer

Reduction occurs at the anode.

Question 36

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

Accepted Answer

Maintain electrical neutrality in both half-cells.

Answer

Prevent the mixing of solutions.

Answer

Provide electrons for the reaction.

Question 37

In an electrolysis cell, what is the cathode's function?

Accepted Answer

Attracts and reduces positive ions (cations).

Answer

Serves as a barrier between electrodes.

Answer

Generates electrons.

Answer

Attracts and oxidizes negative ions (anions).

Question 38

Which of the following is a redox titration?

Accepted Answer

Titration of Fe²⁺ solution with KMnO₄ solution

Answer

Titration of HCl solution with NaOH solution

Answer

Titration of AgNO₃ solution with NaCl solution

Question 39

During oxidation, which of the following changes occur?

Accepted Answer

A substance loses electrons

Answer

A substance gains electrons

Answer

A substance loses hydrogen

Answer

A substance gains oxygen

Question 40

Identify the reducing agent in the reaction: 2Fe3+ + Zn → 2Fe2+ + Zn2+

Accepted Answer

Zn

Answer

Zn2+

Answer

Fe2+

Answer

Fe3+

Question 41

The standard cell potential of a redox reaction provides information about the:

Accepted Answer

Maximum electrical work that can be done by the reaction

Answer

Direction of electron flow in the reaction

Answer

Rate of the reaction

Answer

Equilibrium constant of the reaction

Question 42

The Faraday constant is used to calculate the:

Accepted Answer

Amount of substance deposited or liberated during electrolysis

Answer

Rate of an electrochemical reaction

Answer

Spontaneity of a reaction

Answer

Standard cell potential of a reaction

Question 43

In the reaction 2Fe + 3Cl₂ → 2FeCl₃, which element undergoes oxidation?

Accepted Answer

Iron (Fe)

Answer

None of the above

Answer

Chlorine (Cl₂)

Answer

Iron chloride (FeCl₃)

Question 44

Which of the following substances acts as a reducing agent?

Accepted Answer

Sodium (Na)

Answer

Oxygen (O₂)

Answer

Potassium permanganate (KMnO₄)

Answer

Hydrogen peroxide (H₂O₂)

Question 45

What is the oxidation number of sulfur in sulfuric acid (H₂SO₄)?

Accepted Answer

+6

Answer

+2

Answer

+4

Answer

-2

Question 46

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

Accepted Answer

Anode

Answer

Electrolyte

Answer

Salt bridge

Answer

Cathode

Question 47

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

Accepted Answer

To maintain electrical neutrality in the half-cells

Answer

To provide a pathway for electrons to flow

Answer

To prevent the build-up of charge in the electrolyte

Answer

To increase the rate of the reaction

Question 48

Which of the following processes is NOT an example of electrolysis?

Accepted Answer

The reaction of sodium with chlorine

Answer

The production of aluminum from alumina

Answer

The decomposition of water into hydrogen and oxygen

Answer

The electroplating of silver onto copper

Question 49

During the electrolysis of molten sodium chloride, which ion is reduced at the cathode?

Accepted Answer

Sodium ion (Na⁺)

Answer

Hydrogen ion (H⁺)

Answer

Sodium chloride (NaCl)

Answer

Chloride ion (Cl⁻)

Question 50

The standard electrode potential of a half-cell is measured relative to which standard electrode?

Accepted Answer

The standard hydrogen electrode

Answer

The standard copper electrode

Answer

The standard zinc electrode

Answer

The standard platinum electrode

Question 51

A spontaneous reaction in an electrochemical cell will have a standard cell potential (E°cell) that is:

Accepted Answer

Positive

Answer

Zero

Answer

Negative

Answer

Dependent on the concentration of reactants