Faraday-efficiency effect
The Faraday-efficiency effect refers to the potential for misinterpretation of data from experiments in electrochemistry through failure to take into account a Faraday efficiency of less than 100 percent. == Assumption about efficiency == Until recent decades it was common to assume that the release of hydrogen and oxygen gas during electrolysis of water always has a Faraday efficiency of 100%.
Source: Wikipedia — Faraday-efficiency effect (CC BY-SA 4.0)