Class 12 Chemistry - TAMILNADU
Electrochemistry
Electrochemistry is a crucial chapter in the Class 12 Tamil Nadu Samacheer Kalvi Chemistry curriculum, bridging chemical reactions and electrical energy. It explores how chemical energy is converted into electrical energy in galvanic cells, and vice versa in electrolytic cells. Students will learn about electrochemical cells, Nernst equation, electrolytic conductance, Kohlrausch's law, and commercial batteries like fuel cells. This chapter is exceptionally high-scoring and carries significant weight in the board examinations, frequently featuring numerical problems based on cell potential, Faraday's laws of electrolysis, and molar conductivity calculations.
Start Learning FreeKey Concepts
Electrochemical Cell
A device that converts chemical energy into electrical energy through spontaneous redox reactions, consisting of two half-cells connected by a salt bridge.
Nernst Equation
A mathematical equation that relates the reduction potential of an electrochemical reaction to the standard electrode potential and the activities of chemical species.
Molar Conductivity
The conducting power of all the ions produced by dissolving one mole of an electrolyte in a specific volume of solution.
Kohlrausch's Law
States that the limiting molar conductivity of an electrolyte is the sum of the individual contributions of its constituent anions and cations.
Faraday's Laws of Electrolysis
Quantitative laws that relate the amount of substance deposited at an electrode to the quantity of electric charge passed through the electrolyte.
Important Formulas
Board Exam Info
In the Tamil Nadu Samacheer Kalvi Class 12 Chemistry board exam, Electrochemistry typically carries around 6 to 8 marks. Questions usually include a mix of 1-mark objective questions, 2 or 3-mark direct conceptual or definitional questions, and a mandatory 5-mark problem-solving question involving Nernst equation, Kohlrausch's law applications, or Faraday's laws.
Frequently Asked Questions
What is the function of a salt bridge in an electrochemical cell?
A salt bridge maintains electrical neutrality in the two half-cells by allowing the flow of ions and prevents liquid junction potential between the solutions.
Why does the molar conductivity of a weak electrolyte increase sharply on dilution?
On dilution, the degree of dissociation of a weak electrolyte increases, which significantly increases the total number of ions carrying the current in the solution.
What is the difference between primary and secondary batteries?
Primary batteries are non-rechargeable as the cell reaction occurs only once and gets exhausted over time, whereas secondary batteries are rechargeable and can be reused by passing current in the opposite direction.
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