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Class 12th Chemistry | Galvanic Cell | Measurement of Electrode Potential | Chapter 2

Ignited Minds・2 minutes read

Galveda is an electrochemical cell that converts chemical energy into electrical energy through oxidation and reduction reactions with specific setups and electrode potentials. The standard hydrogen electrode serves as a reference for determining electrode potentials, with positive values indicating good reduction potential and negative values indicating good oxidation potential for elements to undergo oxidation or reduction in cell formation.

Insights

  • Galveda is an electrochemical cell that converts chemical energy into electrical energy through spontaneous reactions, utilizing two half cells for oxidation and reduction, with electrode potential measured in volts.
  • The standard hydrogen electrode serves as a reference point for determining electrode potentials and cell potentials experimentally, with hydrogen's unique ability to undergo both reduction and oxidation reactions making it a crucial standard in electrochemical experiments.

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  • What is Galveda?

    Galveda is an electrochemical cell converting chemical energy to electrical energy.

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Summary

00:00

Galveda: Electrochemical Cell for Energy Conversion

  • Galveda is a type of electrochemical cell that converts chemical energy from spontaneous reactions into electrical energy.
  • It is similar to the Daniel cell, also known as a voltaic cell, where oxidation occurs at the anode and reduction at the cathode.
  • The Galveda setup involves two containers with zinc sulfate and copper sulfate, each containing metal electrodes connected by a wire and a salt bridge for neutrality.
  • The concentration of solutions in Galveda should be one molar, distinguishing it from the Daniell cell.
  • Galveda consists of two half cells, one for oxidation and one for reduction, with the anode being negatively charged and the cathode positively charged.
  • In a single beaker setup, the salt bridge is unnecessary as the connection is completed through the aqueous solution.
  • Different metals can be used in Galveda to observe oxidation and reduction reactions, with electrode potential measured in volts.
  • Standard electrode potential is the potential when all species in a half cell have a concentration of one molar.
  • The cell potential, or electromotive force (EMF), is the potential difference between the cathode and anode electrode potentials, measured in volts.
  • EMF is also known as cell potential and is expressed when no current is drawn through the cell, always considering reduction potentials for electrode potential calculations.

13:55

Understanding Electrochemical Cell Reduction Potentials

  • In an electrochemical cell with zinc and copper electrodes, zinc undergoes oxidation, releasing two electrons, while copper gains these electrons, undergoing reduction.
  • The potential generated from this process is termed reduction potential, as it arises from reduction reactions.
  • Observations in electrochemical cells are always in the form of reduction potentials, not oxidation potentials.
  • The reduction potential of zinc is determined by its conversion to Zinc +2 and the release of 2 electrons.
  • To find the cell potential, reverse the sign of the reduction potential value for the zinc electrode to obtain its oxidation potential.
  • Electrode potential is always considered as reduction potential, crucial for determining cell potential.
  • Cell potential is calculated by subtracting the electrode potential of the anode from that of the cathode.
  • Cell representation involves showcasing the anode and cathode reactions in a simplified manner to derive complete information from the electrochemical cell.
  • The standard hydrogen electrode serves as a reference point for determining electrode potentials and cell potentials experimentally.
  • Hydrogen's unique ability to undergo both reduction and oxidation reactions makes it a standard reference for electrode potential measurements.

27:25

"Standard Hydrogen Electrode: Key in Experiments"

  • Hydrogen is used in experiments to determine electrode potential, with a value of zero indicating equilibrium between oxidation and reduction.
  • The standard hydrogen electrode is used as a reference in experiments to measure cell potential.
  • The setup for the standard hydrogen electrode includes a beaker with a 1 molar acid solution, platinum electrode, and hydrogen gas at one bar pressure.
  • Platinum acts as an inert electrode, providing a surface for reactions without participating in them.
  • Equilibrium is established between hydrogen gas and hydrogen ion on the platinum surface, resulting in an electrode potential of zero.
  • Concentration of species and hydrogen gas pressure are crucial in determining electrode potential using the standard hydrogen electrode.
  • Different inert electrodes like platinum and gold are used when the electrode should not participate in reactions.
  • Standard electrode potential table helps determine which element undergoes oxidation and reduction in a cell setup.
  • Positive values in the electrode potential table indicate good reduction potential, while negative values indicate good oxidation potential.
  • Elements with positive reduction potential act as oxidants, while elements with negative reduction potential act as reducing agents.

41:41

Reduction and Oxidation in Chemical Reactions

  • When gas gains two electrons, it transforms into two fluoride ions, showcasing a reduction process where fluorine acts as an oxidant. Conversely, when fluoride converts back to fluorine by losing two electrons, it undergoes oxidation, indicating its potential as a reduction agent.
  • Observing elements like Lithium, where the reduction of Lithium ions into Lithium occurs by gaining one electron, highlights the principle that elements showing poor reduction tendencies often exhibit strong oxidation reactions. This concept is exemplified by the positioning of copper above hydrogen, indicating good reduction properties, while zinc below hydrogen signifies strong oxidation capabilities. Understanding these tendencies is crucial in determining which elements will undergo oxidation or reduction in electrochemical cell formation based on the standard electrode potential series.
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