Why is the standard reduction potential E, for the standard hydrogen electrode 0.00V?
Please help me explain the reason why to this problem
It is arbritary, and H was decided to be the standard at zero. It could have been someother number, or some other element. H is convenient, and zero is a nice number to compare other numbers to it. Remember H is in many, many chemical reactions.
The standard reduction potential, represented as E°, is a measure of the tendency of a chemical species to gain electrons and undergo reduction. It is relative to the potential of the standard hydrogen electrode (SHE), which is assigned a value of 0.00V.
The reason why the standard reduction potential for the standard hydrogen electrode is 0.00V can be explained by the definition and conventions of the electrode potential scale.
The standard hydrogen electrode consists of a platinum electrode in contact with a 1 M solution of hydrogen ions (H+) at a pressure of 1 atm. The electrode potential is determined by the redox reaction taking place at the electrode surface:
2H+ + 2e- ⟶ H2
The platinum electrode acts as an inert conductor, allowing the transfer of electrons during the redox reaction. Now, the convention is to assign a value of 0.00V to the standard hydrogen electrode potential. This convention is based on several factors:
1. Reference point: In any measurement scale, a reference point is needed. The standard hydrogen electrode provides a reference or benchmark against which all other half-cell potentials are measured. By assigning it a value of 0.00V, all other reduction potentials can be compared directly to it.
2. Standard conditions: The concept of standard conditions is essential in thermodynamics. The standard reduction potential is determined under specific standard conditions, such as 1 M concentration, 1 atm pressure, and a temperature of 25°C. By defining the standard hydrogen electrode potential as 0.00V, it simplifies the calculation of electrode potentials under standard conditions.
3. Arbitrarily chosen: The selection of the standard potential for the standard hydrogen electrode is somewhat arbitrary. It could have been assigned any value, but 0.00V was selected for its simplicity and convenience as a reference point. This choice allows for easier calculations and comparisons of reduction potentials.
To recap, the standard reduction potential for the standard hydrogen electrode is 0.00V based on the definition and conventions of the electrode potential scale. It acts as a reference point against which all other reduction potentials are measured, simplifying calculations and comparisons under standard conditions.