Here below some basic MCQ’s about “Conductance, Cell Potential and Nernst equation” with answer explanation which is explained in details. Let’s check one by one which is given below.
MCQ 1: Conductance
Question: What does the conductance of an electrolyte solution primarily depend on?
A) Concentration of ions
B) Temperature of the solution
C) Nature of the ions
D) All of the above
Answer: D) All of the above
Explanation: The conductance of an electrolyte solution depends on several factors: the concentration of ions (more ions lead to higher conductance), the temperature (higher temperatures typically increase ion mobility), and the nature of the ions (different ions have different mobilities).
MCQ 2: Cell Potential
Question: The cell potential (E) of a galvanic cell can be influenced by which of the following factors?
A) Concentration of reactants and products
B) Temperature
C) The type of electrodes used
D) All of the above
Answer: D) All of the above
Explanation: The cell potential is affected by the concentrations of reactants and products (as described by the Nernst equation), temperature (which can affect reaction rates and equilibrium), and the type of electrodes (different materials can have different standard potentials).
MCQ 3: Nernst Equation
Question: The Nernst equation is used to calculate the cell potential under non-standard conditions. What is the general form of the Nernst equation?
A) E = E° – (RT/nF) ln(Q)
B) E = E° + (RT/nF) ln(Q)
C) E = E° + (nF/RT) ln(Q)
D) E = E° – (nF/RT) ln(Q)
Answer: B) E = E° + (RT/nF) ln(Q)
Explanation: The Nernst equation is used to relate the cell potential (E) to the standard cell potential (E°) and the reaction quotient (Q). The correct form includes a positive sign before the logarithmic term, indicating that as the reaction quotient increases, the cell potential decreases.
MCQ 4: Reaction Quotient
Question: In the context of the Nernst equation, what does the reaction quotient (Q) represent?
A) The ratio of the concentrations of products to reactants at equilibrium
B) The ratio of the concentrations of reactants to products at any moment
C) The standard concentrations of products and reactants
D) The change in concentration of reactants over time
Answer: B) The ratio of the concentrations of reactants to products at any moment
Explanation: The reaction quotient (Q) is defined as the ratio of the concentrations (or activities) of products to reactants at any point in the reaction. It helps to determine the direction in which the reaction will proceed to reach equilibrium.
MCQ 5: Standard Cell Potential
Question: What does a positive standard cell potential (E°) indicate about a galvanic cell?
A) The reaction is spontaneous.
B) The reaction is non-spontaneous.
C) The reaction is at equilibrium.
D) The cell is not functioning.
Answer: A) The reaction is spontaneous.
Explanation: A positive standard cell potential indicates that the electrochemical reaction is spontaneous under standard conditions. This means that the cell can generate electrical energy from the chemical reaction occurring within it.
MCQ 6: Electrolytic vs. Galvanic Cells
Question: Which of the following statements correctly differentiates between electrolytic and galvanic cells?
A) Galvanic cells convert chemical energy to electrical energy; electrolytic cells do the opposite.
B) Electrolytic cells produce energy, while galvanic cells consume energy.
C) Galvanic cells require an external power source; electrolytic cells do not.
D) Both cells operate under the same principles and conditions.
Answer: A) Galvanic cells convert chemical energy to electrical energy; electrolytic cells do the opposite.
Explanation: Galvanic cells generate electrical energy from spontaneous chemical reactions, while electrolytic cells require an external power source to drive non-spontaneous reactions.
MCQ 7: Nernst Equation Application
Question: When applying the Nernst equation, which condition must be met to accurately calculate the cell potential?
A) The temperature must be at room temperature.
B) Concentrations of all species must be known.
C) The reaction must be at equilibrium.
D) Only solid reactants are involved.
Answer: B) Concentrations of all species must be known.
Explanation: To use the Nernst equation effectively, you need to know the concentrations (or activities) of the reactants and products to calculate the reaction quotient (Q).
MCQ 8: Standard Electrode Potential
Question: Which of the following represents a standard condition for measuring standard electrode potentials?
A) 1 M concentration for all solutions
B) 1 atm pressure for gases
C) Temperature at 25°C (298 K)
D) All of the above
Answer: D) All of the above
Explanation: Standard electrode potentials are measured under specific conditions: 1 M concentration for solutions, 1 atm pressure for gases, and at a temperature of 25°C (298 K).
MCQ 9: Ion Mobility
Question: Ion mobility in a solution is primarily affected by which factor?
A) The mass of the ion
B) The charge of the ion
C) The viscosity of the solvent
D) All of the above
Answer: D) All of the above
Explanation: Ion mobility is influenced by the mass and charge of the ion, as well as the viscosity of the solvent, since these factors determine how easily ions can move through the solution.
MCQ 10: Cell Notation
Question: In electrochemical cell notation, which of the following correctly describes the components of the cell?
A) Anode | Oxidation | Cathode | Reduction
B) Anode || Cathode
C) Oxidation || Reduction
D) Cathode | Anode
Answer: B) Anode || Cathode
Explanation: In electrochemical cell notation, the anode and cathode are separated by a double vertical line (||), indicating the salt bridge or membrane between them.
MCQ 11: Conductivity
Question: Which type of solution typically exhibits the highest conductivity?
A) Pure water
B) Distilled water
C) Saltwater
D) Sugar solution
Answer: C) Saltwater
Explanation: Saltwater contains dissolved ions (Na⁺, Cl⁻), which significantly increase its conductivity compared to pure or distilled water, which has very few ions.
MCQ 12: Electrochemical Series
Question: The electrochemical series is useful for determining which of the following?
A) The rate of a reaction
B) The spontaneity of a reaction
C) The pH of a solution
D) The temperature of a cell
Answer: B) The spontaneity of a reaction
Explanation: The electrochemical series ranks standard electrode potentials, which helps predict the spontaneity of redox reactions based on the relative strengths of oxidizing and reducing agents.
MCQ 13: Cell Reactions
Question: In a galvanic cell, what happens at the anode?
A) Oxidation occurs
B) Reduction occurs
C) Electrons are consumed
D) The cell potential increases
Answer: A) Oxidation occurs
Explanation: At the anode of a galvanic cell, oxidation occurs, meaning that the anode loses electrons, which flow to the cathode where reduction takes place.
MCQ 14: Nernst Equation Variables
Question: In the Nernst equation, which variable represents the reaction quotient?
A) E
B) E°
C) Q
D) n
Answer: C) Q
Explanation: In the Nernst equation, Q represents the reaction quotient, which is a measure of the relative concentrations of products and reactants at any given moment.
MCQ 15: Faraday’s Law
Question: According to Faraday’s first law of electrolysis, the mass of substance deposited at an electrode is directly proportional to:
A) The charge passed through the electrolyte
B) The voltage applied
C) The type of electrode used
D) The temperature of the solution
Answer: A) The charge passed through the electrolyte
Explanation: Faraday’s first law states that the mass of substance deposited at an electrode is proportional to the total electric charge (in coulombs) passed through the cell.
MCQ 16: Factors Affecting Electrode Potential
Question: Which factor does NOT affect the electrode potential of a half-cell?
A) Temperature
B) Concentration of ions
C) Size of the electrode
D) Pressure of gases
Answer: C) Size of the electrode
Explanation: While temperature, concentration, and pressure influence electrode potential, the physical size of the electrode does not directly affect the electrode potential.
MCQ 17: Electrolytic Cell
Question: In an electrolytic cell, what role does the power supply play?
A) It allows for spontaneous reactions to occur.
B) It drives the non-spontaneous reaction.
C) It generates heat for the reaction.
D) It provides the necessary ions for conduction.
Answer: B) It drives the non-spontaneous reaction.
Explanation: The power supply in an electrolytic cell provides the necessary energy to drive a non-spontaneous chemical reaction by forcing electrons through the circuit.
MCQ 18: Types of Electrolytes
Question: Which type of electrolyte fully dissociates into ions in solution?
A) Strong electrolyte
B) Weak electrolyte
C) Nonelectrolyte
D) Solvent
Answer: A) Strong electrolyte
Explanation: Strong electrolytes, such as sodium chloride, fully dissociate into ions when dissolved in water, resulting in high conductivity.
MCQ 19: pH and Cell Potential
Question: How does increasing the acidity (lowering pH) of a solution affect the cell potential of an electrochemical cell involving hydrogen ions?
A) Increases the cell potential
B) Decreases the cell potential
C) Has no effect on cell potential
D) It depends on the temperature
Answer: A) Increases the cell potential
Explanation: Increasing the concentration of hydrogen ions (by lowering pH) in a half-cell reaction involving H⁺ ions increases the reaction quotient, thus increasing the cell potential according to the Nernst equation.
MCQ 20: Conductance Units
Question: What is the SI unit of electrical conductance?
A) Ohm
B) Siemens
C) Volt
D) Ampere
Answer: B) Siemens
Explanation: The SI unit of conductance is Siemens (S), which is the reciprocal of resistance measured in ohms.
MCQ 21: Electrode Types
Question: Which of the following is a common type of reference electrode?
A) Copper electrode
B) Silver-silver chloride electrode
C) Carbon electrode
D) Platinum electrode
Answer: B) Silver-silver chloride electrode
Explanation: The silver-silver chloride electrode is widely used as a reference electrode due to its stable potential and ease of preparation.
MCQ 22: Nernst Equation Temperature Dependence
Question: In the Nernst equation, the term RT/nF accounts for changes in which variable?
A) Concentration
B) Temperature
C) Pressure
D) Volume
Answer: B) Temperature
Explanation: The term RT/nF in the Nernst equation indicates that the cell potential is dependent on temperature, where R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons, and F is Faraday’s constant.
MCQ 23: Conductivity Measurement
Question: Which instrument is commonly used to measure the conductivity of a solution?
A) pH meter
B) Conductivity meter
C) Voltmeter
D) Amperometer
Answer: B) Conductivity meter
Explanation: A conductivity meter is specifically designed to measure the electrical conductivity of a solution, indicating its ionic concentration.
MCQ 24: Cell Reaction Direction
Question: In a galvanic cell, the flow of electrons is from:
A) Anode to cathode
B) Cathode to anode
C) Positive to negative terminal
D) None of the above
Answer: A) Anode to cathode
Explanation: Electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs) in a galvanic cell.
MCQ 25: Electrolytic Cell Reactions
Question: What type of reaction occurs at the cathode of an electrolytic cell?
A) Oxidation
B) Reduction
C) Neutralization
D) Hydrolysis
Answer: B) Reduction
Explanation: At the cathode of an electrolytic cell, reduction occurs as electrons are gained by the species at the electrode.
MCQ 26: Effect of Temperature on Conductance
Question: Increasing the temperature of an electrolyte solution typically has what effect on its conductivity?
A) Increases conductivity
B) Decreases conductivity
C) No effect on conductivity
D) Depends on the type of electrolyte
Answer: A) Increases conductivity
Explanation: Higher temperatures increase the mobility of ions in solution, leading to greater conductivity.
MCQ 27: Standard Cell Potential Interpretation
Question: A standard cell potential of 0.00 V indicates that:
A) The reaction is highly spontaneous.
B) The reaction is non-spontaneous.
C) The reaction is at equilibrium.
D) The cell is malfunctioning.
Answer: C) The reaction is at equilibrium.
Explanation: A standard cell potential of 0.00 V suggests that there is no net driving force for the reaction, indicating that it is at equilibrium.
MCQ 28: Reaction Quotient Calculation
Question: If the concentrations of products in a redox reaction are significantly higher than those of the reactants, what will happen to the reaction quotient (Q)?
A) Q will decrease
B) Q will remain constant
C) Q will increase
D) Q will become zero
Answer: C) Q will increase
Explanation: When the concentrations of products are much higher than those of reactants, the reaction quotient (Q) increases, which can affect the cell potential according to the Nernst equation.
MCQ 29: Half-Cell Reactions
Question: In a half-cell reaction, which term describes the species being reduced?
A) Oxidant
B) Reductant
C) Electrode
D) Salt bridge
Answer: A) Oxidant
Explanation: The species that gains electrons (is reduced) in a half-cell reaction is referred to as the oxidant.
MCQ 30: Conductance in Solutions
Question: Which type of electrolyte is characterized by partial dissociation in solution?
A) Strong electrolyte
B) Weak electrolyte
C) Nonelectrolyte
D) Solvent
Answer: B) Weak electrolyte
Explanation: Weak electrolytes only partially dissociate into ions when dissolved in water, resulting in lower conductivity compared to strong electrolytes.
MCQ 31: Electron Flow in Cells
Question: What drives the flow of electrons in an electrochemical cell?
A) Chemical potential difference
B) Thermal energy
C) Magnetic fields
D) Electric field
Answer: A) Chemical potential difference
Explanation: The flow of electrons in an electrochemical cell is driven by the difference in chemical potential between the anode and cathode.
MCQ 32: Electrochemical Reactions
Question: In the reaction Zn + Cu²⁺ → Zn²⁺ + Cu, which species is oxidized?
A) Zn
B) Cu²⁺
C) Zn²⁺
D) Cu
Answer: A) Zn
Explanation: In this reaction, zinc (Zn) loses electrons and is oxidized to zinc ions (Zn²⁺), while copper ions (Cu²⁺) are reduced to solid copper (Cu).
MCQ 33: Relation of Nernst Equation to Equilibrium
Question: The Nernst equation can be used to determine the cell potential at equilibrium. What is the value of E at equilibrium?
A) Positive
B) Negative
C) Zero
D) Undefined
Answer: C) Zero
Explanation: At equilibrium, the cell potential (E) is zero because there is no net change in concentrations of reactants and products.
MCQ 34: Faraday’s Constant
Question: What is the approximate value of Faraday’s constant (F)?
A) 1.6 × 10⁻¹⁹ C/mol
B) 96,485 C/mol
C) 6.022 × 10²³ C/mol
D) 964.85 C/mol
Answer: B) 96,485 C/mol
Explanation: Faraday’s constant (F) is approximately 96,485 coulombs per mole of electrons, representing the charge of one mole of elementary charge carriers.
MCQ 35: Concentration Cells
Question: In a concentration cell, the cell potential arises from:
A) Differences in electrode material
B) Differences in temperature
C) Differences in ion concentration
D) Differences in pressure
Answer: C) Differences in ion concentration
Explanation: The cell potential in a concentration cell is generated due to the difference in concentrations of the same ion on either side of the cell.
MCQ 36: Cell Potential Calculation
Question: Which of the following does NOT affect the cell potential of a galvanic cell?
A) Concentration of the reactants and products
B) Temperature of the system
C) The physical shape of the cell
D) The nature of the electrodes
Answer: C) The physical shape of the cell
Explanation: The physical shape of the galvanic cell does not influence the cell potential; instead, factors like concentration, temperature, and electrode materials do.
MCQ 37: Electrochemical Corrosion
Question: Which of the following is an example of an electrochemical corrosion process?
A) Rusting of iron
B) Oxidation of magnesium
C) Sulfide formation
D) Ion exchange
Answer: A) Rusting of iron
Explanation: Rusting of iron is an electrochemical process where iron oxidizes in the presence of moisture and oxygen, forming iron oxides (rust).
MCQ 38: Polarization in Electrochemical Cells
Question: What is polarization in the context of electrochemical cells?
A) The alignment of dipoles in the electrolyte
B) A reduction in cell potential due to buildup of products
C) An increase in temperature during operation
D) The movement of ions toward the electrodes
Answer: B) A reduction in cell potential due to buildup of products
Explanation: Polarization refers to the decrease in cell potential caused by the accumulation of reaction products at the electrodes, hindering further reaction.
MCQ 39: Standard Hydrogen Electrode (SHE)
Question: What is the purpose of the Standard Hydrogen Electrode (SHE)?
A) It serves as a reference for measuring electrode potentials.
B) It is used to generate electricity.
C) It acts as a strong oxidizing agent.
D) It is a common electrode in galvanic cells.
Answer: A) It serves as a reference for measuring electrode potentials.
Explanation: The Standard Hydrogen Electrode is used as a reference point for measuring and comparing the standard electrode potentials of other half-cells.
MCQ 40: Salt Bridge Function
Question: What is the primary function of a salt bridge in an electrochemical cell?
A) To provide a source of ions
B) To complete the electrical circuit
C) To maintain neutral charge in each half-cell
D) To separate the two half-cells
Answer: C) To maintain neutral charge in each half-cell
Explanation: The salt bridge allows the flow of ions between the half-cells, maintaining charge neutrality by compensating for the movement of electrons through the external circuit.
MCQ 41: Role of Solvents
Question: In an electrochemical cell, what role do solvents play?
A) They provide ions for the reaction.
B) They act as a barrier between electrodes.
C) They alter the standard electrode potential.
D) They increase the cell temperature.
Answer: A) They provide ions for the reaction.
Explanation: Solvents, particularly aqueous solutions, provide ions that facilitate the conduction of electricity and participate in the electrochemical reactions.
MCQ 42: Electrode Reactions
Question: In the reaction 2Ag⁺ + Zn → 2Ag + Zn²⁺, what is being reduced?
A) Ag⁺
B) Zn
C) Zn²⁺
D) None of the above
Answer: A) Ag⁺
Explanation: In this reaction, silver ions (Ag⁺) gain electrons to form solid silver (Ag), indicating that Ag⁺ is being reduced.
MCQ 43: Cell Efficiency
Question: What is the maximum efficiency of an electrochemical cell?
A) 50%
B) 75%
C) 100%
D) It varies based on the cell design
Answer: C) 100%
Explanation: Theoretically, an electrochemical cell can be 100% efficient in converting chemical energy into electrical energy. However, practical cells often have lower efficiencies due to losses like polarization and resistance.
MCQ 44: Electrode Potential Calculations
Question: The standard electrode potential (E°) of a half-reaction is determined by:
A) The concentration of products only
B) The concentration of reactants only
C) The concentrations of both reactants and products
D) The temperature of the system only
Answer: C) The concentrations of both reactants and products
Explanation: The standard electrode potential (E°) is affected by the concentrations of both reactants and products in the electrochemical reaction, as described by the Nernst equation.
MCQ 45: Conductivity in Different Solutions
Question: Which of the following solutions would likely have the lowest conductivity?
A) 0.1 M NaCl
B) 0.1 M HCl
C) 0.1 M CH₃COOH
D) 0.1 M KBr
Answer: C) 0.1 M CH₃COOH
Explanation: Acetic acid (CH₃COOH) is a weak electrolyte and only partially dissociates in solution, leading to lower conductivity compared to the strong electrolytes NaCl, HCl, and KBr.
MCQ 46: Nernst Equation Constants
Question: In the Nernst equation, what do the variables R, T, n, and F represent?
A) R = gas constant, T = temperature, n = moles of electrons, F = Faraday’s constant
B) R = resistance, T = temperature, n = number of ions, F = Faraday’s constant
C) R = rate of reaction, T = time, n = number of electrons, F = force
D) R = resistivity, T = temperature, n = number of moles, F = Faraday’s number
Answer: A) R = gas constant, T = temperature, n = moles of electrons, F = Faraday’s constant
Explanation: In the Nernst equation, R is the universal gas constant, T is the absolute temperature in Kelvin, n is the number of moles of electrons transferred in the reaction, and F is Faraday’s constant.
MCQ 47: Electrochemical Cells and Batteries
Question: Which of the following is a primary difference between primary and secondary batteries?
A) Primary batteries can be recharged; secondary cannot.
B) Secondary batteries can be recharged; primary cannot.
C) Primary batteries have a higher energy density than secondary.
D) Secondary batteries are always larger than primary batteries.
Answer: B) Secondary batteries can be recharged; primary cannot.
Explanation: Primary batteries are designed for single-use and cannot be recharged, while secondary batteries can be recharged and reused multiple times.
MCQ 48: Reversible vs. Irreversible Cells
Question: A reversible electrochemical cell is characterized by:
A) Spontaneous reactions only
B) The ability to return to initial conditions
C) Higher efficiency than irreversible cells
D) All of the above
Answer: D) All of the above
Explanation: Reversible electrochemical cells can operate in both directions, allowing them to return to their initial conditions, and typically have higher efficiencies than irreversible cells.
MCQ 49: Ion Migration
Question: In an electrolytic cell, anions migrate toward the:
A) Anode
B) Cathode
C) Salt bridge
D) Electrolyte
Answer: A) Anode
Explanation: In an electrolytic cell, negatively charged ions (anions) migrate toward the anode, where oxidation occurs.
MCQ 50: Cell Potential Significance
Question: The sign of the cell potential (E) indicates:
A) The direction of electron flow
B) The temperature of the cell
C) The concentration of ions
D) The type of reaction occurring
Answer: A) The direction of electron flow
Explanation: The sign of the cell potential indicates whether the reaction is spontaneous (positive E) or non-spontaneous (negative E) and thus the direction of electron flow.
MCQ 51: Effect of Concentration on Cell Potential
Question: If the concentration of reactants in a galvanic cell increases, what happens to the cell potential?
A) It decreases
B) It remains the same
C) It increases
D) It becomes zero
Answer: C) It increases
Explanation: According to the Nernst equation, increasing the concentration of reactants shifts the equilibrium toward the products, increasing the cell potential.
MCQ 52: Half-Cell Definitions
Question: A half-cell consists of:
A) Only an anode
B) Only a cathode
C) An electrode and its corresponding electrolyte
D) Only a salt bridge
Answer: C) An electrode and its corresponding electrolyte
Explanation: A half-cell is made up of an electrode in contact with an electrolyte solution that contains ions participating in the electrochemical reaction.
MCQ 53: Conductance and Temperature
Question: What is the general effect of temperature on the conductance of a solution?
A) Decreases with increasing temperature
B) Increases with increasing temperature
C) No significant effect
D) Only affects solid conductors
Answer: B) Increases with increasing temperature
Explanation: Increasing the temperature typically enhances the mobility of ions in a solution, thereby increasing its conductance.
MCQ 54: Ion Selectivity
Question: Which ion is most commonly used in the reference electrode for measuring pH?
A) Sodium ion (Na⁺)
B) Potassium ion (K⁺)
C) Hydrogen ion (H⁺)
D) Silver ion (Ag⁺)
Answer: C) Hydrogen ion (H⁺)
Explanation: The hydrogen ion concentration is critical for pH measurement, making it essential for reference electrodes used in pH meters.
MCQ 55: Discharge of Ions
Question: During electrolysis, which ion is likely to discharge at the cathode in an aqueous solution?
A) Na⁺
B) H⁺
C) Cl⁻
D) OH⁻
Answer: B) H⁺
Explanation: In aqueous solutions, hydrogen ions (H⁺) are typically discharged at the cathode due to their higher reduction potential compared to other cations like Na⁺.
MCQ 56: Standard Electrode Potentials
Question: The standard electrode potential is a measure of:
A) The ability of an electrode to conduct electricity
B) The tendency of a species to be reduced
C) The concentration of ions in solution
D) The temperature of the electrolyte
Answer: B) The tendency of a species to be reduced
Explanation: Standard electrode potentials indicate how easily a species can gain electrons and be reduced, providing insight into its reactivity.
MCQ 57: Corrosion Prevention
Question: Which method is commonly used to prevent corrosion in metals?
A) Painting
B) Galvanization
C) Cathodic protection
D) All of the above
Answer: D) All of the above
Explanation: Various methods such as painting, galvanization, and cathodic protection are used to prevent corrosion by isolating the metal from the environment or by providing a sacrificial anode.
MCQ 58: Electrolyte Function
Question: In an electrolytic cell, the electrolyte serves primarily to:
A) Provide thermal energy
B) Allow ion migration
C) Act as a barrier
D) Maintain constant temperature
Answer: B) Allow ion migration
Explanation: The electrolyte provides the medium for ion migration between the anode and cathode, enabling the electrochemical reaction to occur.
MCQ 59: Nernst Equation Factors
Question: In the Nernst equation, what does a negative cell potential indicate?
A) The reaction is spontaneous.
B) The reaction is non-spontaneous.
C) The system is at equilibrium.
D) The temperature is too low.
Answer: B) The reaction is non-spontaneous.
Explanation: A negative cell potential suggests that the electrochemical reaction is not spontaneous under the given conditions and requires an external energy source to proceed.
MCQ 60: Voltaic Cell
Question: A voltaic cell generates electricity from:
A) Heat
B) Light
C) Spontaneous chemical reactions
D) External electrical sources
Answer: C) Spontaneous chemical reactions
Explanation: A voltaic cell, also known as a galvanic cell, converts the energy released from spontaneous chemical reactions into electrical energy.
MCQ 61: Corrosion Rate Factors
Question: Which of the following factors does NOT significantly affect the rate of corrosion?
A) Temperature
B) Presence of salts
C) Size of the metal
D) Humidity
Answer: C) Size of the metal
Explanation: While temperature, presence of salts, and humidity significantly influence the rate of corrosion, the size of the metal has less impact on the corrosion rate itself.
MCQ 62: Faraday’s Second Law
Question: Faraday’s second law of electrolysis states that:
A) The mass of substance produced is inversely proportional to the charge.
B) The mass of substance produced is directly proportional to the charge.
C) The current is constant during electrolysis.
D) Voltage determines the amount of gas produced.
Answer: B) The mass of substance produced is directly proportional to the charge.
Explanation: Faraday’s second law states that the amount of substance produced at an electrode during electrolysis is directly proportional to the total electric charge passed through the electrolyte.
MCQ 63: Electrochemical Cell Types
Question: Which type of electrochemical cell is primarily used in batteries?
A) Electrolytic cells
B) Voltaic cells
C) Concentration cells
D) All of the above
Answer: B) Voltaic cells
Explanation: Voltaic cells, or galvanic cells, are primarily used in batteries to convert chemical energy into electrical energy.
MCQ 64: Nernst Equation Variables
Question: In the Nernst equation, what does the variable “E” represent?
A) Equilibrium constant
B) Cell potential
C) Electrode potential
D) Energy consumed
Answer: B) Cell potential
Explanation: In the Nernst equation, “E” represents the cell potential under non-standard conditions, indicating the driving force for the electrochemical reaction.
MCQ 65: Conductivity in Strong Electrolytes
Question: Strong electrolytes dissociate completely in solution. Which of the following is a strong electrolyte?
A) Acetic acid
B) Ammonium chloride
C) Glucose
D) Ethanol
Answer: B) Ammonium chloride
Explanation: Ammonium chloride (NH₄Cl) is a strong electrolyte that dissociates completely into ions in solution, while acetic acid is a weak electrolyte and glucose and ethanol do not ionize.
MCQ 66: Cell Components
Question: The anode in an electrochemical cell is where:
A) Reduction occurs
B) Oxidation occurs
C) Electrons are gained
D) Cations migrate
Answer: B) Oxidation occurs
Explanation: The anode is the electrode where oxidation takes place, resulting in the loss of electrons.
MCQ 67: Influence of pH on Cell Potential
Question: In a redox reaction involving hydrogen ions, how does a decrease in pH affect the cell potential?
A) It has no effect
B) It increases cell potential
C) It decreases cell potential
D) It can either increase or decrease depending on temperature
Answer: B) It increases cell potential
Explanation: A decrease in pH (increased concentration of H⁺ ions) typically increases the cell potential in reactions involving hydrogen ions according to the Nernst equation.
MCQ 68: Salt Bridge Composition
Question: What is typically used to fill a salt bridge in an electrochemical cell?
A) Water
B) Salt solution (e.g., KCl)
C) Acidic solution
D) Sugar solution
Answer: B) Salt solution (e.g., KCl)
Explanation: A salt bridge is commonly filled with a concentrated salt solution, such as potassium chloride (KCl), to maintain ion flow and electrical neutrality.
MCQ 69: Reduction Potential
Question: A higher reduction potential indicates that a substance:
A) Is a better oxidizing agent
B) Is a better reducing agent
C) Cannot undergo redox reactions
D) Is unstable
Answer: A) Is a better oxidizing agent
Explanation: A higher reduction potential means that a substance is more likely to gain electrons and be reduced, making it a stronger oxidizing agent.
MCQ 70: Electrochemical Series Application
Question: The electrochemical series is used to predict:
A) The equilibrium constant of a reaction
B) The spontaneity of redox reactions
C) The temperature of a solution
D) The pressure of gases in a reaction
Answer: B) The spontaneity of redox reactions
Explanation: The electrochemical series allows chemists to predict which reactions will be spontaneous based on the relative strengths of oxidizing and reducing agents.
MCQ 71: Cell Potential and Concentration
Question: According to the Nernst equation, if the concentration of a reactant decreases, what happens to the cell potential?
A) Increases
B) Decreases
C) Remains constant
D) Becomes zero
Answer: B) Decreases
Explanation: A decrease in the concentration of a reactant reduces the driving force for the reaction, thus decreasing the cell potential.
MCQ 72: Redox Reactions
Question: In a redox reaction, what is the role of the oxidizing agent?
A) It is reduced and gains electrons
B) It is oxidized and loses electrons
C) It acts as a catalyst
D) It has no effect on the reaction
Answer: A) It is reduced and gains electrons
Explanation: The oxidizing agent undergoes reduction by gaining electrons, facilitating the oxidation of another substance.
MCQ 73: Electrolytic Cell Power Supply
Question: What type of power supply is typically used in electrolytic cells?
A) AC power supply
B) DC power supply
C) Solar power
D) Mechanical power
Answer: B) DC power supply
Explanation: A direct current (DC) power supply is used in electrolytic cells to drive the non-spontaneous redox reactions.
MCQ 74: Standard Electrode Potential Value
Question: The standard electrode potential for a half-cell reaction is determined under which conditions?
A) At 0°C and 1 atm
B) At 25°C, 1 atm, and 1 M concentration
C) At room temperature and varying pressures
D) At 100°C and 1 atm
Answer: B) At 25°C, 1 atm, and 1 M concentration
Explanation: Standard electrode potentials are measured at 25°C (298 K), 1 atm pressure, and with reactant and product concentrations at 1 M.
MCQ 75: Measuring Electrode Potentials
Question: Which instrument is used to measure the potential difference between two electrodes?
A) Amperometer
B) Potentiometer
C) Voltmeter
D) Thermometer
Answer: C) Voltmeter
Explanation: A voltmeter is used to measure the potential difference (voltage) between two electrodes in an electrochemical cell.
MCQ 76: Ion Transport Mechanisms
Question: How do ions typically move in an electrolytic solution?
A) Randomly, without direction
B) Toward electrodes of opposite charge
C) Only in response to an external magnetic field
D) In a straight line with no collisions
Answer: B) Toward electrodes of opposite charge
Explanation: Ions migrate toward electrodes of opposite charge due to the electric field created by the applied voltage in the electrolytic solution.
MCQ 77: Conductivity and Ionic Strength
Question: As the ionic strength of a solution increases, what typically happens to its conductivity?
A) Conductivity decreases
B) Conductivity remains constant
C) Conductivity increases
D) Conductivity becomes unpredictable
Answer: C) Conductivity increases
Explanation: Increasing ionic strength typically leads to a greater number of charge carriers in solution, thereby increasing conductivity.
MCQ 78: Galvanic Cell Components
Question: Which of the following components is essential for a galvanic cell to function?
A) Only anode
B) Only cathode
C) A salt bridge
D) All of the above
Answer: D) All of the above
Explanation: A galvanic cell requires both an anode and a cathode, as well as a salt bridge to maintain charge neutrality and allow for the flow of ions.
MCQ 79: Reaction Quotient (Q) and Equilibrium
Question: The reaction quotient (Q) at equilibrium is:
A) Greater than 1
B) Less than 1
C) Equal to the equilibrium constant (K)
D) Always zero
Answer: C) Equal to the equilibrium constant (K)
Explanation: At equilibrium, the reaction quotient (Q) is equal to the equilibrium constant (K), indicating a balance between the concentrations of reactants and products.
MCQ 80: Factors Influencing Electrode Reaction Rates
Question: Which of the following factors does NOT significantly influence the rate of an electrode reaction?
A) Surface area of the electrode
B) Temperature of the solution
C) The color of the electrolyte
D) Concentration of reactants
Answer: C) The color of the electrolyte
Explanation: The color of the electrolyte does not affect the rate of electrode reactions, while factors such as surface area, temperature, and concentration have significant impacts.
MCQ 81: Primary vs. Secondary Cells
Question: Which of the following is a characteristic of secondary cells?
A) They cannot be recharged.
B) They have a fixed voltage.
C) They can undergo multiple charge-discharge cycles.
D) They are always smaller than primary cells.
Answer: C) They can undergo multiple charge-discharge cycles.
Explanation: Secondary cells, or rechargeable batteries, can be cycled multiple times, allowing for repeated charging and discharging.
MCQ 82: Oxidation Numbers
Question: In a redox reaction, the change in oxidation number of an element indicates:
A) The total mass change of the reaction.
B) The loss or gain of electrons.
C) The concentration of reactants.
D) The energy change of the reaction.
Answer: B) The loss or gain of electrons.
Explanation: Changes in oxidation numbers reflect the transfer of electrons during redox reactions, with increases indicating oxidation and decreases indicating reduction.
MCQ 83: Ionic Mobility
Question: Which ion generally has the highest mobility in solution?
A) Na⁺
B) Cl⁻
C) K⁺
D) Ca²⁺
Answer: A) Na⁺
Explanation: Sodium ions (Na⁺) typically exhibit higher mobility in aqueous solutions compared to other common ions, facilitating faster conduction.
MCQ 84: Electrode Reactions in Batteries
Question: In a lithium-ion battery, lithium ions move from:
A) Anode to cathode during discharge
B) Cathode to anode during discharge
C) Anode to cathode during charging
D) Cathode to anode during charging
Answer: A) Anode to cathode during discharge
Explanation: During discharge, lithium ions move from the anode to the cathode, where they participate in the electrochemical reaction that generates electricity.
MCQ 85: Cell Potential Calculation
Question: In the Nernst equation, what does the term RTnFnFRT represent?
A) Temperature correction factor
B) Standard cell potential
C) Change in Gibbs free energy
D) Concentration of ions
Answer: A) Temperature correction factor
Explanation: The term RTnFnFRT in the Nernst equation adjusts the cell potential based on temperature, where R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons, and F is Faraday’s constant.
MCQ 86: Role of a Salt Bridge
Question: The primary function of a salt bridge in an electrochemical cell is to:
A) Facilitate electron flow.
B) Maintain electrical neutrality.
C) Increase the concentration of ions.
D) Isolate the electrodes.
Answer: B) Maintain electrical neutrality.
Explanation: The salt bridge allows ions to migrate between the two half-cells, maintaining charge balance and preventing the buildup of charge that would stop the reaction.
MCQ 87: Electrochemical Cell Reactions
Question: In a Daniell cell, which metal acts as the anode?
A) Copper
B) Zinc
C) Silver
D) Gold
Answer: B) Zinc
Explanation: In a Daniell cell, zinc serves as the anode, where it undergoes oxidation, while copper acts as the cathode where reduction occurs.
MCQ 88: Conductance Measurement
Question: What unit is commonly used to express conductivity?
A) Ohm
B) Siemens
C) Volt
D) Coulomb
Answer: B) Siemens
Explanation: Conductivity is measured in siemens (S), which quantifies how well a solution conducts electricity.
MCQ 89: Reaction Quotient (Q)
Question: When calculating the reaction quotient (Q), which of the following is considered?
A) Concentrations of only reactants
B) Concentrations of only products
C) Concentrations of both reactants and products
D) Temperature of the solution only
Answer: C) Concentrations of both reactants and products
Explanation: The reaction quotient (Q) is calculated using the concentrations of both reactants and products at any point during the reaction.
MCQ 90: Electrolysis Products
Question: During the electrolysis of water, what gases are produced at the electrodes?
A) Nitrogen and oxygen
B) Hydrogen and chlorine
C) Hydrogen and oxygen
D) Carbon dioxide and hydrogen
Answer: C) Hydrogen and oxygen
Explanation: Electrolysis of water produces hydrogen gas at the cathode and oxygen gas at the anode.
MCQ 91: Relationship Between Current and Conductance
Question: The relationship between current (I), voltage (V), and conductance (G) is described by which formula?
A) I=G⋅V
B) I=V⋅G
C) V=I⋅G
D) V=IG
Answer: A) I=G⋅V
Explanation: The current (I) through a conductor is equal to the product of the conductance (G) and the voltage (V) applied across it.
MCQ 92: Cell Voltage Measurement
Question: When measuring the voltage of a cell, a positive voltage indicates:
A) A non-spontaneous reaction.
B) A spontaneous reaction.
C) No reaction occurring.
D) The presence of an external power source.
Answer: B) A spontaneous reaction.
Explanation: A positive cell voltage indicates that the electrochemical reaction is spontaneous and will proceed without external energy input.
MCQ 93: Nernst Equation Adaptation
Question: The Nernst equation can be adapted to account for temperature changes by incorporating:
A) The van’t Hoff equation
B) The Arrhenius equation
C) Temperature coefficients
D) The modified reaction quotient
Answer: C) Temperature coefficients
Explanation: The Nernst equation can be adjusted by including temperature coefficients to account for how temperature affects the cell potential.
MCQ 94: Oxidation State Changes
Question: In the reaction Zn+Cu2+→Zn2++Cu, which element is oxidized?
A) Zinc
B) Copper
C) Both zinc and copper
D) Neither
Answer: A) Zinc
Explanation: Zinc is oxidized as it loses electrons and changes from elemental zinc (0 oxidation state) to zinc ions (+2 oxidation state).
MCQ 95: Conductance Measurement Units
Question: What is the SI unit for measuring electric current, which also relates to conductance?
A) Ohm
B) Volt
C) Ampere
D) Siemens
Answer: C) Ampere
Explanation: The ampere (A) is the SI unit for electric current, and it is directly related to conductance, as conductance determines how much current flows for a given voltage.
MCQ 96: Electrochemical Cell Types
Question: Which type of electrochemical cell requires an external power source to operate?
A) Galvanic cell
B) Electrolytic cell
C) Fuel cell
D) Concentration cell
Answer: B) Electrolytic cell
Explanation: An electrolytic cell requires an external power source to drive non-spontaneous reactions, while galvanic cells generate electricity from spontaneous reactions.
MCQ 97: Factors Affecting Conductance
Question: Which of the following factors most directly affects the conductance of an electrolyte solution?
A) The color of the solution
B) The presence of solid impurities
C) The concentration of ions
D) The volume of the solution
Answer: C) The concentration of ions
Explanation: The conductance of an electrolyte solution is directly proportional to the concentration of ions present, as more ions facilitate greater current flow.
MCQ 98: Cell Reaction Direction
Question: In a galvanic cell, the direction of electron flow is from:
A) Cathode to anode
B) Anode to cathode
C) Both electrodes simultaneously
D) Depends on the cell type
Answer: B) Anode to cathode
Explanation: In a galvanic cell, electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs).
MCQ 99: Cathode Reactions
Question: In an electrochemical cell, the cathode is defined as the electrode where:
A) Reduction occurs
B) Oxidation occurs
C) Current enters the cell
D) Ions are neutralized
Answer: A) Reduction occurs
Explanation: The cathode is the electrode at which reduction takes place, meaning it gains electrons during the electrochemical reaction.
MCQ 100: Energy Conversion in Electrochemical Cells
Question: What type of energy conversion occurs in a galvanic cell?
A) Chemical to mechanical
B) Mechanical to electrical
C) Chemical to electrical
D) Electrical to thermal
Answer: C) Chemical to electrical
Explanation: In a galvanic cell, chemical energy stored in reactants is converted into electrical energy during the spontaneous redox reactions
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