What had Faraday concluded based on his electrochemical experiments ?
In the late 19th century , Josiah Willard Gibbs had formulated a theory to predict whether a chemical reaction is spontaneous based on the free energy ΔG = ΔG° + RT·ln (Q) Here " ΔG " is change in Gibbs free energy , " ΔG° " is the cell potential when " Q " is equal to 1 , " T " is absolute temperature ( Kelvin ) , " R " is the gas constant and " Q " is reaction quotient which can be found by dividing products by reactants using only those products and reactants that are aqueous or gaseous .