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Electrochemistry Class 12 One Shot | Class 12 Chemistry Chapter 3 | Electrochemistry | Aravind Arora

VEDANTU NEET MADE EJEE・2 minutes read

Galvanic cells convert chemical energy into electrical energy, while electrolytic cells convert electrical energy into chemical energy. Standard electrode potential is crucial for determining the overall electromotive force of a cell, and conductance in an electrolytic cell is determined by the reciprocal of resistance.

Insights

  • Galvanic cells convert chemical energy into electrical energy, while electrolytic cells convert electrical energy into chemical energy, showcasing the fundamental difference in their operations.
  • The Nernst equation is essential for understanding electrochemical cells, providing a crucial tool to calculate cell potential at non-standard conditions and establish equilibrium, emphasizing its significance in electrochemistry studies.

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Recent questions

  • What are the two types of electrochemical cells?

    Galvanic and electrolytic cells.

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Summary

00:00

"Electrochemical Cells: Galvanic vs. Electrolytic"

  • There are two types of electrochemical cells: galvanic and electrolytic cells.
  • Electrochemistry is divided into three parts: galvanic cell, electrolytic cell, and electrolytic solution.
  • Galvanic cells convert chemical energy into electrical energy, while electrolytic cells convert electrical energy into chemical energy.
  • Galvanic cells have chemical input and electrical output, while electrolytic cells have electrical input and chemical output.
  • Galvanic cells have spontaneous reactions, while electrolytic cells have non-spontaneous reactions.
  • Spontaneous reactions have a negative delta G value, while non-spontaneous reactions have a positive delta G value.
  • Anode and cathode electrodes in galvanic cells are in separate containers, while in electrolytic cells, they are in the same container.
  • Anode is the positive terminal and cathode is the negative terminal in galvanic cells, while it is the opposite in electrolytic cells.
  • Anode is where oxidation occurs, and cathode is where reduction occurs.
  • Examples of galvanic cells include the Daniel cell.

14:02

Daniel Cell: Zinc, Copper, and Salt Bridge

  • Daniel cell involves placing a zinc rod and filling it with ZnSO4 solution.
  • The cathode of copper is placed in an aqua solution of CuSO4.
  • Connecting the components forms the Daniel cell, allowing current flow.
  • The salt bridge completes the circuit and maintains electrical neutrality.
  • Zinc converts to Zn+2, releasing two electrons, while copper is converted by liberating two electrons.
  • The Daniel cell is a complete structure with zinc, copper, and a salt bridge.
  • Representing the cell involves indicating oxidation and reduction on the left and right sides.
  • Electrode potential is generated by separating charges, as in a capacitor.
  • Oxidation potential is created on the left side, reduction potential on the right.
  • Standard electrode potential is calculated under specific conditions, aiding in determining the cell's overall electromotive force (emf).

27:03

IMF Calculation and Electrochemical Cell Equilibrium

  • To find the IMF of the entire cell, consider the standard conditions, noting that it is the sum of reduction potential and oxidation potential.
  • The electrode potential of the cathode is the reduction potential, while the oxidation potential belongs to the anode.
  • The oxidation potential is represented by the reduction potential, and the formula for the cell is A not of cathode - A not of anode.
  • Remember to use the correct formula, A not of cathode - A not of anode, to avoid errors in calculations.
  • The electrochemical series is based on the standard hydrogen electrode potential, with fluorine having the most positive reduction potential and lithium the most negative.
  • Fluorine is a strong oxidizing agent, while lithium is a potent reducing agent due to their reduction potentials.
  • The Nernst equation is crucial for electrochemical cells, with the equation being A = A not - 0.059 / n log of the reaction coefficient.
  • Establishing equilibrium in a cell means A becomes zero, and the equation for equilibrium is A = A not - 0.059 / n log of the reaction coefficient.
  • The value of delta G in a cell is determined by the EOD cell, with a positive EOD cell value indicating a negative delta G and vice versa.
  • Conductance in an electrolytic cell is determined by the reciprocal of resistance, with conductance being 1 / resistance and conductivity being 1 / resistivity.

40:17

Conductivity and Dilution in Electrolytic Solutions

  • The cell constant is represented as 1/ and conductivity is equal to conductance in cell constant.
  • Conductivity is measured in units of conductors and resistance is measured in Ohms.
  • Conductivity, or kappa, decreases when an electrolytic solution is diluted with water.
  • Dilution increases the free space for charges to move, leading to an increase in conductance.
  • Molar conductance and equivalent conductance increase with dilution, while conductivity decreases.
  • Kohlrausch's law explains the variation of conductivity with concentration for strong electrolytes.
  • Strong electrolytes show a distinct graph behavior with a point at infinity, indicating 100% ionization.
  • Weak electrolytes exhibit a different graph behavior due to lower degree of ionization.
  • The calculation of molar conductivity involves adding the values of charges at infinity to determine the limiting molar conductivity.
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