unit of electricity, used in the study of electrochemical reactions (electrochemical reaction) and equal to the amount of electric charge that liberates one gram equivalent of any ion from an electrolytic solution. It was named in honour of the 19th-century English scientist Michael Faraday (Faraday, Michael) and equals 9.64853399 × 10⁴ coulombs (coulomb), or 6.02214179 × 10²³ electrons (electron) (see also Avogadro's law).