The activity coefficients of m- and p-dichlorobenzene in aqueous salt solns. have been determine at 298.15K by using spectrophotometric method. The salts used are NaF, NaBr, KBr, Na2CO3, K2SO4, Et4NBr. The relations between logf and cs are in agreement with Setschenow experimental formula. The salting-out order is: Na2CO3 > K2SO4 > NaF > NaCl > NaBr > KBr > Et4NBr. The salt effect is not affected by the dipole moment of dichlorobenzene. The experimental results are compared with the calculation results of Debye-McAulay and Conway-Desnoyers-Smith electrostatic theories, scaled particle theory, and internal pressure theory. The numerical calculation of the modified internal pressure theory gives the best fit with the experimental data.

Key words: AQUEOUS SOLUTION, SODIUM CARBONATE, SODIUM CHLORIDE, POTASSIUM SULFATE, SODIUM FLUORIDE, SALT EFFECT, POTASSIUM BROMIDE, DICHLOROBENZENE, ACTIVITY COEFFICIENT, SODIUM BROMIDE