Using such formulation, we can estimate the ion dissociation of neat RTIL and RTIL/solvent mixture. One can observe the significance of the eq. ( ) that the present methodology of ion mobility comprised of ion dissociation requires concentration of ionic liquid (cIL), ionic conductivity (σ) measured by EIS and molal volume of ions at normal boiling point (υ) calculated by Schotte's method. In addition, a relation between ion dissociation and equilibrium constant through thermodynamic chemistry is given in section S1 (Supporting Information). It further relates the activity coefficient of the ions with ion dissociation.