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.
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