Studies on surface tension of the system: Barium soap‐water and propanol‐1

The surface tension results of the barium soap solutions in water‐propanol‐1 mixtures have been explained on the basis of Szyszkowski's empirical equation: γ = γ o (1 + X ln Y) ‐ X γ o ln C. The values of the constants X and Y of the equation have been calculated for various soap systems. The constant X is found to be almost independent of the composition of the solvent mixture but it depends to some extent on the chain length of the soap. The values of Y show a marked increase at 50% propanol‐1 concentration which confirms that the transition in the nature of the micelles takes place at about 50% propanol‐1 concentration. The values of X and Y are suggestive of the size and nature of the micelles, respectively.