Questions and Answers
What type of electrochemical cell uses the energy released during a spontaneous redox reaction?
Anode is located on the right-hand side of a galvanic cell.
False
What is the significance of EMF in a cell?
Electromotive force indicates the feasibility of the cell operation.
A galvanic cell is also called a _____ cell.
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What occurs at the cathode during the electrolysis of molten NaCl?
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Which of the following represents the half cell reaction at the anode during the electrolysis of molten NaCl?
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What happens during the electrolysis of water?
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The standard reduction potentials for Cd and Cu2+ are _____ V and _____ V respectively, where Cd is -0.40 V and Cu2+ is 0.34 V.
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What is generated at the cathode in a Galvanic cell during a redox reaction?
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Study Notes
Electrochemical Cells
- Devices that generate electricity from spontaneous redox reactions or use electricity to drive non-spontaneous redox reactions.
- Comprise two electrodes (anode and cathode) and an electrolyte.
- Commonly linked by a metal wire; copper is often used.
Types of Electrochemical Cells
- Galvanic (Voltaic) Cells: Utilize energy from spontaneous redox reactions (ΔG < 0) to produce electricity.
- Named after Alessandro Volta, the inventor of this cell type.
Galvanic Cell Representation
- Anode (oxidation) is on the left; cathode (reduction) is on the right.
- Example: Zn|Zn(NO3)2 (1M) || Cu(NO3)2 (1M)|Cu demonstrates oxidation and reduction processes.
Flow of Electrons and Current
- Electrons flow from anode to cathode; current flows in the opposite direction.
- Cell feasibility: feasible if EMF is positive; not feasible if EMF is negative.
Calculating Standard EMF of a Cell
- Standard EMF can be calculated using the standard reduction potentials of the involved metals.
- Example calculation involves Zn (-0.76 V) and Ag (+0.80 V) to determine overall EMF.
Nernst Equation and Electrochemical Calculations
- Essential for calculating cell potentials under non-standard conditions.
- Used to determine equilibrium constants and analyze half-cell reactions.
Electrolysis of Molten NaCl
- Na+ ions are reduced to Na at the cathode, and Cl- ions are oxidized to Cl2 at the anode.
- The electrolysis process occurs at approximately 801 °C using inert electrodes.
Inert Electrodes in Electrolysis
- Inert electrodes, like graphite rods, do not participate in the chemical reactions.
- Power supply is needed to drive electron movement from anode to cathode.
Electrolysis of Water
- Involves a pair of inert electrodes submerged in water; applying voltage promotes the decomposition of water into hydrogen and oxygen gases.
Key Reactions in Electrochemical Processes
- For electrolysis of NaCl: 2 NaCl (l) → 2 Na (l) + Cl2 (g) at the anode.
- Importance of maintaining ion movement during electrolysis to ensure continuous reactions.
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Description
This quiz covers Module 4 of Engineering Chemistry BCHY101L, focusing on energy devices. Topics include electrochemical cells, electrode materials, lithium-ion batteries, supercapacitors, fuel cells, and solar cells. Test your knowledge on these essential technologies that power various applications in modern engineering.
