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Chapter Analysis
Advanced29 pages • EnglishQuick Summary
This chapter on electrochemistry explores the conversion between chemical and electrical energy, focusing on galvanic and electrolytic cells. It discusses the fundamental principles of electrochemical cells, including the Daniell cell, electrode potential, and the use of the Nernst equation to calculate cell potentials. The chapter also covers applications such as corrosion, batteries, and fuel cells, highlighting the environmental impact and sustainability of hydrogen fuel.
Key Topics
- •Electrochemical cells and their functioning
- •Nernst equation and its applications
- •Calculation of electrode and cell potentials
- •Corrosion processes and prevention
- •Battery and fuel cell technologies
- •Hydrogen economy and sustainability
- •Faraday's laws of electrolysis
Learning Objectives
- ✓Understand the principles of galvanic and electrolytic cells.
- ✓Calculate cell potential using the Nernst equation.
- ✓Identify applications of electrochemical cells in industry.
- ✓Explain corrosion as an electrochemical process and how to prevent it.
- ✓Describe the operation and benefits of batteries and fuel cells.
- ✓Discuss the role of electrochemistry in the hydrogen economy.
Questions in Chapter
Arrange the following metals in the order in which they displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn.
Page 59
Depict the galvanic cell in which the reaction Zn(s)+2Ag+(aq) ®Zn2+(aq)+2Ag(s) takes place. Further show: (i) Which of the electrode is negatively charged? (ii) The carriers of the current in the cell. (iii) Individual reaction at each electrode.
Page 60
Write the Nernst equation and emf of the following cells at 298 K: (i) Mg(s)|Mg2+(0.001M)||Cu2+(0.0001 M)|Cu(s)
Answer: E(cell) = Eo(cell) - (RT/nF) ln([Zn^2+]/[Cu^2+])
Page 60
In the button cells widely used in watches and other devices the following reaction takes place: Zn(s) + Ag2O(s) + H2O(l ) ® Zn2+(aq) + 2Ag(s) + 2OH–(aq) Determine DrGo and Eo for the reaction.
Page 60
Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.
Page 60
The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 S cm–1. Calculate its molar conductivity.
Page 60
Additional Practice Questions
What role do electrolytic conductors play in an electrochemical cell?
mediumAnswer: Electrolytic conductors allow the passage of ions in an electrochemical cell, facilitating the redox reactions necessary for the cell's operation. The electrolytic solution completes the internal circuit and enables ion transfer between electrodes.
How is the standard electrode potential of an electrode determined?
hardAnswer: Standard electrode potentials are determined by connecting the electrode of interest with a standard hydrogen electrode, which is set at zero potential, serving as a reference. The potential difference measured is the electrode's standard potential.
Explain the impact of concentration on cell potential using the Nernst equation.
mediumAnswer: According to the Nernst equation, cell potential decreases with increasing concentration of products and increases with increasing concentration of reactants. This reflects in the logarithmic term (RT/nF) ln(Q), where Q is the reaction quotient.
What are the environmental benefits of using hydrogen fuel cells?
easyAnswer: Hydrogen fuel cells offer environmental benefits by producing only water as a byproduct, thus reducing greenhouse gas emissions from fossil fuel combustion. They contribute to cleaner energy solutions and help mitigate climate change.
How can corrosion be prevented using electrochemical methods?
hardAnswer: Corrosion can be prevented by using sacrificial anodes that corrode instead of the protected metal, or by coating the metal with a protective layer of another less reactive metal.