What is a redox potential?
Redox potential, also known as the standard electrode potential, is a measure of how easily the substance loses or acquires electrons during reducing oxidation-or "redox"-the chemical reaction where one reactant decreases and the other oxidized. The electrons move from the reduction agent to the oxidation agent. This can be expressed as an electrical potential between them and measured in volts. The negative value indicates a reduction agent with a tendency to lose electrons and a positive value indicates an oxidation agent with a tendency to obtain electrons. Redox potential is sometimes marked E °. It is therefore rather relative than the absolute value. In order to determine the standard values of elements, compounds and ions, redox potential measurements against and the "standard" of hydrogen, which is considered zero, so all such values are relative to hydrogen.
For determination E ° for a given substance is constructed electrochemical BA knob consisting of two half cells. One consists of H+ ions and neutral hydrogen in balance and is known as a standard hydrogen electrode. The second contains a substance to be tested, again ionic and neutral forms in balance. Both are connected by a salt bridge containing a suitable electrolyte and the cell is associated with a voltmeter and completes the perimeter. Where there is a difference in redox potential, electrons try to flow in one way or another, which creates a potential difference that is measured by voltmeter-in this case, a high resistance voltmeter is used to prevent any actual current flow because it would reduce potential.
If the electrons flow from the bus to the other, the substance has a positive redox potential and is an oxidation agent in this context. If the electrons flow in the opposite way, E ° is negative, which points to the reduction agent. The terms 'oxidation' and 'reduction' as used here are relative to hydrogen - the chemicals tested can behave differently with respect to Jinema of the reagent. For example, in this scenario, hydrogen acts as a reduction or oxidizing agent, depending on what is in the second half of the cell.
In this way, a standard redox potential table has been compiled that shows E ° values for different "half reactions" including the addition of electrons to the agent, as if this were the same in one half of the redox reaction. For example, the redox potential for the lithium ion obtaining an electron is displayed as half the reaction: if + + E