The Goldman-Hodgkin-Katz variation of this equation can be used for multiple ions at a non-equilibrium steady state, while some pH meters reverse its most common usage by utilizing measured voltage to determine hydrogen ion  concentration.
The Goldman-Hodgkin-Katz variation of this equation can be used for multiple ions at a non-equilibrium steady state, while some pH meters reverse its most common usage by utilizing measured voltage to determine hydrogen ion  concentration. In one form, it can be stated as ―delta G equals delta G naught plus R times T times the natural log of Q,‖  though at standard temperature and pressure, the equation converts to a Faraday constant-containing form relating the  electrical potential of a cell to a standard potential. FTP, name this central electrochemistry equation named after the 1920 Nobel Laureate in Chemistry.
The Goldman-Hodgkin-Katz variation of this equation can be used for multiple ions at a non-equilibrium steady state, while some pH meters reverse its most common usage by utilizing measured voltage to determine hydrogen ion  concentration.
Nernst equation