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.
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