81. Which of the following metals is commonly used in electroplating to protect steel from corrosion?
- a) Lead
- b) Zinc
- c) Copper
- d) Aluminum
Answer: b) Zinc
Explanation: Zinc is commonly used to electroplate steel to protect it from corrosion through a process called galvanization.
82. The standard electrode potential of a hydrogen electrode is assigned a value of:
- a) 1V
- b) -1V
- c) 0V
- d) +1V
Answer: c) 0V
Explanation: The standard hydrogen electrode (SHE) is defined to have a standard electrode potential of exactly 0V, and it serves as the reference point for measuring other electrode potentials.
83. In an electrolytic cell, the cathode is:
- a) Positively charged
- b) Negatively charged
- c) Neutral
- d) Dependent on the electrolyte
Answer: b) Negatively charged
Explanation: In an electrolytic cell, the cathode is negatively charged because it attracts cations (positive ions) for reduction.
84. Which metal is commonly used for the cathode in a nickel-cadmium battery?
- a) Nickel oxide
- b) Zinc oxide
- c) Copper oxide
- d) Silver oxide
Answer: a) Nickel oxide
Explanation: In a nickel-cadmium battery, the cathode material is typically nickel oxide hydroxide (NiOOH), which undergoes reduction during discharge.
85. What is the function of the porous partition in a Leclanché cell?
- a) To allow ions to pass between electrodes
- b) To prevent electron flow
- c) To separate different chemicals
- d) To prevent gases from escaping
Answer: a) To allow ions to pass between electrodes
Explanation: The porous partition in a Leclanché cell allows ions to pass between the electrodes while preventing the mixing of chemicals that could cause short-circuiting.
86. Which of the following gases is released at the anode during the electrolysis of molten sodium chloride?
- a) Oxygen
- b) Chlorine
- c) Hydrogen
- d) Nitrogen
Answer: b) Chlorine
Explanation: During the electrolysis of molten sodium chloride, chlorine gas is released at the anode due to the oxidation of chloride ions.
87. Which type of electrolyte is used in a lead-acid storage battery?
- a) Hydrochloric acid
- b) Sulfuric acid
- c) Nitric acid
- d) Acetic acid
Answer: b) Sulfuric acid
Explanation: Lead-acid storage batteries use sulfuric acid (H₂SO₄) as the electrolyte, which facilitates the electrochemical reactions between the lead and lead dioxide electrodes.
88. Which of the following is the correct expression for Faraday’s second law of electrolysis?
- a) The amount of substance deposited is directly proportional to the current
- b) The mass of the substance deposited is directly proportional to the charge
- c) The mass of the substance deposited is directly proportional to the equivalent weight
- d) The equivalent weight of the substance deposited is directly proportional to the number of electrons involved
Answer: c) The mass of the substance deposited is directly proportional to the equivalent weight
Explanation: Faraday’s second law of electrolysis states that the mass of the substance deposited or liberated at an electrode is directly proportional to its equivalent weight.
89. The standard cell potential of a galvanic cell is:
- a) Always negative
- b) Always positive
- c) Zero
- d) Dependent on the reaction conditions
Answer: b) Always positive
Explanation: The standard cell potential of a galvanic cell is always positive, indicating a spontaneous reaction.
90. Which of the following materials is commonly used as the cathode in an alkaline battery?
- a) Zinc
- b) Copper
- c) Manganese dioxide
- d) Nickel oxide
Answer: c) Manganese dioxide
Explanation: In alkaline batteries, manganese dioxide (MnO₂) is used as the cathode material, where it undergoes reduction during discharge.
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