Water electrolysis
= Water electrolysis
<Water electrolysis> uses electrical work to convert <water> into <hydrogen> and <oxygen>. For the net reaction, two water molecules produce two hydrogen molecules and one oxygen molecule; four <electrons> pass through the external circuit per reaction as written.
The reversible voltage follows from the reaction's <Gibbs free energy> under specified conditions. Finite operating <electric current> additionally requires kinetic and transport driving forces and incurs resistive losses, so operating voltage exceeds the reversible requirement.