Q1. What is the branch of chemistry that deals with the study of the interconversion of electrical energy and chemical energy?
a) Organic chemistry
b) Electrochemistry
c) Inorganic chemistry
d) Analytical chemistry
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Correct Answer: b) Electrochemistry
Explanation: Electrochemistry is the branch of chemistry that deals with the study of the interconversion of electrical energy and chemical energy in chemical reactions. It involves the application of principles from both chemistry and physics to understand how electrons move during redox reactions and how these movements can be harnessed to produce electricity or drive non-spontaneous chemical reactions. Electrochemistry has significant applications in various fields, including energy storage (batteries and fuel cells), corrosion protection, electroplating, electrolysis, sensors, and environmental remediation. Understanding electrochemistry is crucial for advancing technologies related to renewable energy, electrochemical synthesis, and materials science.
Q2. What is the process by which electrical energy is converted into chemical energy in an electrochemical cell?
a) Oxidation
b) Reduction
c) Electrolysis
d) Galvanization
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Correct Answer: c) Electrolysis
Explanation: Electrolysis is the process by which electrical energy is used to drive a non-spontaneous chemical reaction, resulting in the conversion of electrical energy into chemical energy. It involves the passage of an electric current through an electrolyte, causing the decomposition of the electrolyte into its constituent ions, which then undergo oxidation or reduction at the electrodes. Electrolysis has various practical applications, including electroplating, metal refining, water electrolysis for hydrogen production, and the synthesis of chemical compounds. Understanding the principles of electrolysis is essential for optimizing electrochemical processes and designing efficient energy storage and conversion systems.
Q3. In an electrochemical cell, where do oxidation and reduction reactions occur?
a) Anode and cathode, respectively
b) Cathode and anode, respectively
c) Salt bridge
d) Electrolyte solution
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Correct Answer: a) Anode and cathode, respectively
Explanation: In an electrochemical cell, oxidation occurs at the anode, and reduction occurs at the cathode. The anode is the electrode where oxidation takes place, resulting in the loss of electrons, while the cathode is the electrode where reduction occurs, involving the gain of electrons. The movement of electrons from the anode to the cathode generates an electric current, which can be harnessed for various applications. The separation of oxidation and reduction reactions allows electrochemical cells to produce electrical energy from chemical reactions or drive non-spontaneous chemical processes through the input of electrical energy.
Q4. What type of electrochemical cell generates electrical energy from spontaneous chemical reactions?
a) Galvanic cell
b) Electrolytic cell
c) Voltaic cell
d) Electroplating cell
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Correct Answer: a) Galvanic cell
Explanation: A galvanic cell, also known as a voltaic cell, is an electrochemical cell that generates electrical energy from spontaneous chemical reactions. In a galvanic cell, oxidation occurs at the anode, and reduction occurs at the cathode, producing an electric potential difference (voltage) between the two electrodes. This potential difference drives the flow of electrons through an external circuit, generating an electric current that can power external devices. Galvanic cells are commonly used in batteries to provide portable power for electronic devices, vehicles, and other applications.
Q5. Which law states that the amount of chemical change produced by passing an electric current through an electrolyte is proportional to the quantity of electricity passed through the electrolyte?
a) Faraday’s law of electrolysis
b) Ohm’s law
c) Coulomb’s law
d) Boyle’s law
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Correct Answer: a) Faraday’s law of electrolysis
Explanation: Faraday’s law of electrolysis, formulated by the British scientist Michael Faraday, states that the amount of chemical change produced by passing an electric current through an electrolyte is proportional to the quantity of electricity passed through the electrolyte. Mathematically, Faraday’s law can be expressed as “m = zFQ,” where “m” is the mass of the substance produced or consumed, “z” is the number of moles of electrons transferred in the reaction, “F” is Faraday’s constant (the charge of one mole of electrons), and “Q” is the quantity of electricity passed (measured in coulombs).
Q6. What is the device used to measure the electric potential difference between two electrodes in an electrochemical cell?
a) Voltmeter
b) Ammeter
c) Galvanometer
d) Rheostat
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Correct Answer: a) Voltmeter
Explanation: A voltmeter is the device used to measure the electric potential difference (voltage) between two electrodes in an electrochemical cell or any electrical circuit. It is typically connected in parallel to the components across which the voltage is to be measured. Voltmeters are calibrated in units of volts (V) and provide a numerical readout of the voltage magnitude. In an electrochemical cell, the voltage measured by a voltmeter reflects the difference in electrical potential between the cathode and the anode, which drives the flow of electrons through the external circuit.
Q7. What is the SI unit of electrical charge used in electrochemistry?
a) Coulomb (C)
b) Ampere (A)
c) Volt (V)
d) Ohm (Ω)
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Correct Answer: a) Coulomb (C)
Explanation: The SI unit of electrical charge used in electrochemistry is the Coulomb (C). Named after the French physicist Charles-Augustin de Coulomb, the Coulomb is defined as the charge transported by a constant current of one ampere in one second. It is equivalent to approximately 6.242 × 10^18 elementary charges, where an elementary charge represents the charge carried by a single proton or electron. In electrochemical calculations, the Coulomb is commonly used to quantify the amount of electric charge passed through an electrochemical cell during a given electrochemical process, such as electrolysis or battery discharge. Understanding the Coulomb as a fundamental unit of charge is essential for analyzing and interpreting electrochemical phenomena and processes accurately.
Q8. Which electrochemical process involves the application of an external electric current to drive a non-spontaneous chemical reaction?
a) Electroplating
b) Galvanization
c) Oxidation
d) Reduction
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Correct Answer: a) Electroplating
Explanation: Electroplating is the electrochemical process that involves the deposition of a metal coating onto a conductive surface by applying an external electric current. It is commonly used to improve the appearance, corrosion resistance, and durability of metal objects. During electroplating, the object to be plated (cathode) and a metal electrode (anode) are immersed in an electrolyte solution containing ions of the plating metal. When an electric current is passed through the electrolyte, metal ions from the anode are oxidized and deposited onto the cathode, forming a thin, uniform metal coating. Electroplating finds widespread applications in industries such as automotive, electronics, jewelry, and manufacturing.
Q9. Which principle states that the total electric charge in a closed system remains constant over time, regardless of any chemical reactions or physical processes occurring within the system?
a) Faraday’s law of electrolysis
b) Coulomb’s law
c) Kirchhoff’s law
d) Law of conservation of charge
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Correct Answer: d) Law of conservation of charge
Explanation: The law of conservation of charge, a fundamental principle in physics and electrochemistry, states that the total electric charge in a closed system remains constant over time, regardless of any chemical reactions or physical processes occurring within the system. In other words, electric charge cannot be created or destroyed but can only be transferred from one object to another or converted between different forms (e.g., from electrical to chemical energy in batteries). The conservation of charge plays a crucial role in electrochemical reactions, circuit analysis, and the understanding of fundamental electromagnetic phenomena.
Q10. What is the process by which a metal surface undergoes corrosion due to the electrochemical reaction between the metal and its environment?
a) Oxidation
b) Reduction
c) Electrolysis
d) Galvanization
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Correct Answer: a) Oxidation
Explanation: Oxidation is the process by which a metal surface undergoes corrosion due to the electrochemical reaction between the metal and its environment, typically involving the loss of electrons from the metal atoms. In the context of corrosion, oxidation occurs at the metal surface, where metal atoms are oxidized to form metal cations (ions) and electrons, which are released into the surrounding medium. The released electrons can then flow through the metal to areas where reduction reactions occur, completing the electrochemical corrosion process. Oxidation is a common mechanism of deterioration for metals exposed to moisture, oxygen, acids, and other corrosive agents, leading to structural damage and material degradation over time.