Question

The standard electrode use to reference all electrode potentials to is? A.chlorine/chloride B.Cu2+/copper C.proton/hydrogen D.Zn2+/zinc

Answer 1

Answer : C

Proton / Hydrogen

since its potential takes as E = 0 volts.

most of metal can give hydrogen gas when react with acid so it is consider as standard hydrogen electrode.

First an initial discharge allows electrons to fill into the highest occupied energy level of Pt. As this is done, some of the H+ ions form H3O+ ions with the water molecules in the solution. These hydrogen and hydronium ions then get close enough to the Pt electrode (on the platinized surface of this electrode) to where a hydrogen is attracted to the electrons in the metal and forms a hydrogen atom. Then these combine with other hydrogen atoms to create H2(g). This hydrogen gas is released from the system. In order to keep the reaction going, the electrode requires a constant flow of H2(g). The Pt wire is connected to a similar electrode in which the opposite process is occurring, thus producing a charge that is referenced at 0 volts. Other standard electrodes are usually preferred because the SHE can be a difficult electrode to set up. The difficulty arises in the preparation of the platinized surface and in controlling the concentration of the reactants. For this reason the SHE is referred to as a hypothetical electrode.