Electrochemistry Quizzes: Test Your Understanding of Redox Reactions and Electrochemical Cells

Question 1

In a redox reaction, a positive standard cell potential indicates that:

Accepted Answer

The reaction proceeds spontaneously from reactants to products.

Answer

The reaction proceeds spontaneously from products to reactants.

Answer

The reaction is at equilibrium.

Answer

The reaction is not spontaneous in either direction.

Question 2

In an electrochemical cell, oxidation occurs at the:

Accepted Answer

Anode

Answer

Cathode

Answer

Salt bridge

Answer

Electrolyte solution

Question 3

The standard reduction potential of a half-reaction represents:

Accepted Answer

The tendency for the half-reaction to occur

Answer

The rate at which the half-reaction proceeds

Answer

The overall energy change of the half-reaction

Answer

The equilibrium constant of the half-reaction

Question 4

Potentiometry is a technique primarily used to:

Accepted Answer

Measure the concentration of specific ions in a solution

Answer

Determine the equilibrium constant of a reaction

Answer

Predict the reaction products

Answer

Calculate the standard reduction potential of a half-reaction

Question 5

The Nernst equation establishes a relationship between:

Accepted Answer

The EMF of an electrochemical cell and the concentrations of reactants and products

Answer

The Gibbs free energy change of a reaction and the equilibrium constant

Answer

The rate of a reaction and the temperature

Answer

The standard reduction potential of a half-reaction and the concentration of reactants

Question 6

Electrochemical impedance spectroscopy (EIS) is a technique designed to:

Accepted Answer

Investigate the electrical properties of electrochemical systems

Answer

Measure the concentration of ions in solution

Answer

Determine the rate of a reaction

Answer

Predict the products of a reaction

Question 7

In a galvanic cell, the anode is the electrode where:

Accepted Answer

Oxidation occurs

Answer

Reduction occurs

Answer

Electrons flow from

Answer

Electrons flow to

Question 8

The Nernst equation can be used to calculate:

Accepted Answer

The cell potential under non-standard conditions

Answer

The standard cell potential

Answer

The equilibrium constant of the cell reaction

Answer

The concentration of reactants and products

Question 9

A potentiometric titration is used to determine the:

Accepted Answer

Concentration of an unknown solution

Answer

Standard reduction potential of a half-reaction

Answer

EMF of an electrochemical cell

Answer

Equilibrium constant of a chemical reaction

Question 10

The Debye-Hückel limiting law is used to:

Accepted Answer

Estimate the activity coefficients of ions in dilute solutions

Answer

Calculate the standard reduction potential of a half-reaction

Answer

Predict the EMF of an electrochemical cell

Answer

Determine the concentration of an unknown solution

Question 11

Identify the reaction that does NOT represent a redox reaction:

Accepted Answer

2Na + Cl₂ → 2NaCl

Answer

Zn + 2HCl → ZnCl₂ + H₂

Answer

Fe²⁺ + Cu²⁺ → Fe³⁺ + Cu⁺

Answer

H₂O → H₂ + ½O₂

Question 12

What is the primary use of the Nernst equation in electrochemistry?

Accepted Answer

Calculating cell potential

Answer

Determining reaction spontaneity

Answer

Finding equilibrium constants

Answer

Measuring pH

Question 13

Which of the following is NOT a type of potentiometric sensor?

Accepted Answer

Spectrophotometer

Answer

pH electrode

Answer

Ion-selective electrode

Answer

Conductivity meter

Question 14

What is the main purpose of a reference electrode?

Accepted Answer

Provide a stable potential reference

Answer

Measure working electrode potential

Answer

Complete the electrochemical cell circuit

Answer

Prevent current flow between electrodes

Question 15

A galvanic cell has a standard cell potential of 2.20 V. When the cell is run at 298 K, the measured cell potential is 1.47 V. What is the ratio of the concentrations of the reactants to the products?

Accepted Answer

0.1

Answer

1

Answer

10

Answer

100

Question 16

What is the accepted standard reduction potential of the hydrogen electrode under standard conditions?

Accepted Answer

0.00 V

Answer

-0.41 V

Answer

1.23 V

Answer

2.00 V

Question 17

Which factor does NOT influence the electromotive force (EMF) of an electrochemical cell?

Accepted Answer

Type of cell container

Answer

Concentrations of reactants and products

Answer

Temperature

Answer

Surface area of electrodes

Question 18

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

Accepted Answer

To complete the electrical circuit and enable ion flow.

Answer

To prevent the mixing of solutions.

Answer

To act as an electron reservoir.

Answer

To measure the voltage difference between the electrodes.

Question 19

What is the primary application of the Nernst equation?

Accepted Answer

Calculating the cell potential of an electrochemical cell

Answer

Determining the concentration of a solution

Answer

Measuring the pH of a solution

Answer

Predicting the equilibrium constant of a reaction

Question 20

In a galvanic cell, where does oxidation take place?

Accepted Answer

Anode

Answer

Cathode

Answer

Both the anode and cathode

Answer

Neither the anode nor the cathode

Question 21

In a galvanic cell constructed using a zinc electrode and a copper electrode, which electrode will undergo oxidation?

Accepted Answer

Zinc

Answer

Copper

Question 22

Which factor does NOT affect the potential of an electrochemical cell?

Accepted Answer

Cell size

Answer

Concentration of reactants

Answer

Temperature

Answer

Nature of electrodes

Question 23

Which of the following expressions represents the Nernst equation?

Accepted Answer

E = E° - (RT/nF)lnQ

Answer

E = E° + (RT/nF)lnQ

Answer

E = E° - (RT/nF)ln(Q/K)

Answer

E = E° + (RT/nF)ln(K/Q)

Question 24

Which metal exhibits the highest resistance to corrosion?

Accepted Answer

Gold

Answer

Iron

Answer

Copper

Answer

Aluminum

Question 25

Identify the type of electrochemical cell in which an external power source is used to drive a chemical reaction?

Accepted Answer

Electrolytic cell

Answer

Galvanic cell

Answer

Fuel cell

Question 26

Which of the following half-reactions represents the reduction of oxygen?

Accepted Answer

O2 + 4H+ + 4e- -> 2H2O

Answer

O2 + 2H+ + 2e- -> H2O2

Answer

O2 + e- -> O-

Answer

O2 + 2e- -> 2O-

Question 27

How does potentiometry determine the concentration of an unknown acid using a known base?

Accepted Answer

By measuring the voltage difference between a reference electrode and an indicator electrode in the solution.

Answer

By measuring the current flowing through the solution with a known voltage applied.

Answer

By observing the pH change as the base is added.

Answer

By measuring the mass of acid added to the solution.

Question 28

Which of the following is NOT a type of electrochemical cell?

Accepted Answer

Homogeneous cell

Answer

Fuel cell

Answer

Galvanic cell

Answer

Electrolytic cell

Question 29

What is the standard reduction potential of the standard hydrogen electrode (SHE) in volts?

Accepted Answer

0 V

Answer

1 V

Answer

0.5 V

Answer

-1 V

Question 30

In a Daniel cell, which electrode is the anode?

Accepted Answer

Zinc (Zn) electrode

Answer

Salt bridge

Answer

Copper (Cu) electrode

Answer

Voltmeter

Question 31

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

Accepted Answer

To maintain electrical neutrality and complete the circuit

Answer

To prevent the mixing of solutions

Answer

To generate a potential difference

Question 32

What is the key distinction between a galvanic cell and an electrolytic cell?

Accepted Answer

In a galvanic cell, the reaction occurs spontaneously, while in an electrolytic cell, it is non-spontaneous.

Answer

In a galvanic cell, the anode is positive, while in an electrolytic cell, it is negative.

Question 33

In the dichromate ion (Cr2O7^2-), chromium has an oxidation number of:

Accepted Answer

+6

Answer

-6

Answer

+3

Answer

+4

Question 34

A galvanic cell is constructed with the following half-reactions:

1/2 Fe^2+(aq) + e- → Fe(s)
E° = -0.44 V

1/2 O2(g) + H2O(l) + 2e- → 2OH-(aq)
E° = +0.40 V

What is the cell potential of this galvanic cell?

Accepted Answer

0.84 V

Answer

-0.84 V

Answer

0.04 V

Question 35

Which of the following substances is classified as a strong electrolyte?

Accepted Answer

NaCl

Answer

NH3

Answer

CH3OH

Answer

C6H12O6

Question 36

In an electrochemical cell, what is the role of the cathode?

Accepted Answer

Site of reduction

Answer

Electrolyte

Answer

Anode

Answer

Site of oxidation

Question 37

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

Accepted Answer

Maintain electrical neutrality

Answer

Act as a catalyst

Answer

Prevent solution mixing

Answer

Increase cell potential

Question 38

The Nernst equation is primarily used to calculate:

Accepted Answer

Cell potential under non-standard conditions

Answer

Reaction spontaneity

Answer

Equilibrium constant

Question 39

Which of the following is the oxidation state of chromium in the complex ion [Cr(NH3)6]³⁺?

Accepted Answer

+3

Answer

+6

Answer

+2

Answer

+1

Question 40

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

Accepted Answer

2 Cu⁺ → Cu + Cu²⁺

Answer

Fe²⁺ + 2 Cl⁻ → FeCl2

Answer

Cu + 2 Ag⁺ → Cu²⁺ + 2 Ag

Answer

Zn + 2 HCl → ZnCl2 + H2

Question 41

What is the standard reduction potential (E°) of the half-reaction: Fe³⁺ + e⁻ → Fe²⁺?

Accepted Answer

+0.77 V

Answer

+2.00 V

Answer

-0.77 V

Answer

-2.00 V

Question 42

What is the Nernst equation primarily used for?

Accepted Answer

Calculating the cell potential of an electrochemical cell under non-standard conditions

Answer

Measuring the concentration of an analyte in a solution

Answer

Determining the equilibrium constant of a redox reaction

Question 43

Identify the strong electrolyte among the following compounds:

Accepted Answer

NaCl

Answer

NH3

Answer

C6H12O6

Answer

CH3OH

Question 44

What is the unit of the Faraday constant?

Accepted Answer

Coulombs per mole

Answer

Joules

Answer

Joules per mole Kelvin

Answer

Liters atmospheres per mole Kelvin

Question 45

Which of the following processes occurs at the cathode in an electrochemical cell?

Accepted Answer

Reduction

Answer

Neutralization

Answer

Oxidation

Answer

Hydrolysis

Question 46

Which of the following is NOT a type of electrochemical cell?

Accepted Answer

Photovoltaic cell

Answer

Electrolytic cell

Answer

Galvanic cell

Answer

Fuel cell

Question 47

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

Accepted Answer

0 V

Answer

2 V

Answer

-1 V

Answer

1 V

Question 48

Identify the reaction that represents a redox reaction:

Accepted Answer

2Fe + 3Cl₂ → 2FeCl₃

Answer

CH₄ + 2O₂ → CO₂ + 2H₂O

Answer

CaCO₃ → CaO + CO₂

Answer

NaCl + H₂O → NaOH + HCl

Question 49

State the primary purpose of the Nernst equation:

Accepted Answer

To calculate the cell potential of an electrochemical cell under non-standard conditions.

Answer

To determine the standard reduction potential of an electrode.

Answer

To calculate the equilibrium constant of a redox reaction.

Question 50

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

Accepted Answer

To maintain electrical neutrality in the cell.

Answer

To enhance the cell's conductivity.

Answer

To serve as an ion source for the reaction.

Answer

To prevent the mixing of the two half-cells.

Question 51

Describe the relationship between the cell potential (E) and the Gibbs free energy change (ΔG) of a reaction:

Accepted Answer

E = -ΔG / nF

Answer

E = nF / ΔG

Answer

E = ΔG

Question 52

Define the standard hydrogen electrode (SHE).

Accepted Answer

A reference electrode with a reduction potential of 0 V.

Answer

A reference electrode with a reduction potential of -1 V.

Answer

A reference electrode with a reduction potential of 1 V.

Question 53

State the purpose of a potentiostat in electrochemistry:

Accepted Answer

To control the potential of an electrochemical cell.

Answer

To measure the current flowing through an electrochemical cell.

Answer

To generate a voltage ramp for cyclic voltammetry.