Class 12 Chemistry - KERALA
Electrochemistry
Electrochemistry is a crucial chapter in the Class 12 Kerala SCERT Chemistry syllabus that explores the interconversion of chemical and electrical energy. It covers electrochemical cells, standard electrode potentials, the Nernst equation relating cell potential to concentration, and electrolytic conductance. You will also learn about commercial cells like batteries and fuel cells, as well as the phenomenon of corrosion. This chapter carries significant weight in the board exams, frequently featuring both conceptual reasoning questions and numerical problems based on Nernst equation, Faraday's laws of electrolysis, and molar conductivity.
Start Learning FreeKey Concepts
Electrochemical Cells
Devices like Daniel cells that convert chemical energy of spontaneous redox reactions into electrical energy, consisting of two half-cells connected by a salt bridge.
Nernst Equation
An equation that relates the reduction potential of an electrochemical reaction to the standard electrode potential, temperature, and activities (or concentrations) of chemical species.
Molar Conductivity
The conducting power of all the ions produced by dissolving one mole of an electrolyte in a given solution, which increases with dilution.
Kohlrausch's Law
States that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of its constituent anions and cations.
Faraday's Laws of Electrolysis
Quantitative laws stating that the amount of chemical change during electrolysis is proportional to the electricity passed, and for different substances, proportional to their equivalent masses.
Important Formulas
Board Exam Info
In the Kerala (SCERT) Class 12 Chemistry board examination, Electrochemistry typically carries around 6 to 8 marks. Questions usually include 1-mark objective questions, 2-mark conceptual questions regarding the salt bridge or corrosion, and 3-mark numerical problems based on the Nernst equation, Kohlrausch's law, or Faraday's laws of electrolysis.
Frequently Asked Questions
What is the function of a salt bridge in an electrochemical cell?
A salt bridge completes the electrical circuit and maintains electrical neutrality in the two half-cells by allowing the flow of ions without mixing the solutions.
Why does molar conductivity increase with dilution for weak electrolytes?
With dilution, the degree of dissociation of weak electrolytes increases, which significantly increases the total number of ions carrying current in the solution.
Can we measure the absolute potential of a single electrode?
No, it is thermodynamically impossible to measure the absolute potential of a single half-cell. We can only measure the difference in potential between two electrodes by coupling it with a Standard Hydrogen Electrode (SHE).
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