Question

What do you mean by standard hydrogen electrode?

Short answer

#tag_title# Short Answer # The Standard Hydrogen Electrode (SHE) is a reference electrode used to measure the reduction potentials of half-cell reactions in electrochemical cells under standard conditions. It is assigned a potential of 0 volts and consists of a platinum electrode, hydrogen gas, and an acidic solution. The SHE provides a stable reference point for consistently comparing and measuring redox potentials of different species, which is essential in various scientific applications such as electrochemistry and metabolism research.

Step-by-step solution

Definition of Standard Hydrogen Electrode (SHE) #

The Standard Hydrogen Electrode (SHE) is a reference electrode used to measure the reduction potentials of half-cell reactions in electrochemical cells. It is designed to provide a stable and reproducible reference point for comparing and measuring redox potentials of different species under standard conditions. The SHE is assigned a potential of 0 volts, which provides a convenient reference for the measurements of other half-cell reactions involving other redox couples. #

Components of SHE #

The SHE consists of the following components: 1. A platinum electrode: The platinum electrode is an inert conductor that serves as a platform for the redox reaction. Platinum is chosen for its non-reactivity and good electrical conductivity. 2. Hydrogen Gas: Hydrogen gas is continuously bubbled through the solution at a pressure of 1 atm. 3. Acidic Solution: The electrode is immersed in an acidic solution with a hydrogen ion concentration of 1 M (usually 1 M HCl solution is used).

Functioning of SHE #

When the SHE is used in an electrochemical cell, hydrogen gas is oxidized on the surface of the platinum electrode, releasing electrons to the electrode. This electron flow generates an electric potential, which can be measured against the potential of the other half-cell reaction taking place in the cell. Mathematically, the half-cell reaction at the SHE is given by: 2H+(aq) + 2e- ⇌ H2(g) At standard conditions (1 M hydrogen ion concentration, 1 atm hydrogen gas pressure, and 25°C temperature), the SHE's potential is defined as zero volts. This potential is used as a reference for measuring the potentials of other half-cell reactions and assigning a relative reduction potential to each reaction. #

Importance of SHE #

The SHE is crucial in providing a consistent and reliable reference point for determining the reduction potentials of a wide range of redox reactions. Reduction potentials give insights into the spontaneous flow of electrons in redox processes, which is valuable in many scientific applications, particularly in electrochemistry and metabolism research. By providing standard conditions and a reference point, SHE allows researchers to compare and study various redox reactions accurately and consistently.