Individual Activities of Sodium and Chloride Ions In Aqueous Solutions of Sodium Chloride

The emf's in aqueous solutions of NaCl were measured with a Na glass electrode and a Ag/AgCl electrode, each opposed by a calomel electrode, and opposing each other. A procedure was followed which yields reproducible results despite the change of Eo of the electrodes. The liquid junction potentials were calculated by the Henderson equation. Activity coefficients of the neutral NaCl and of the individual ions were calculated and compared with γ±Nacl and with γ±Nacl and γNa+ obtained with the Maclnnes assumption. The potentiometric behavior observed is consistent with the use of the Maclnnes assumption and with the liquid junction potentials calculated.