Conductometric investigations of rubidium soaps in water and alkanols

Abstract

The critical micelle concentration (CMC), limiting equivalent conductance and dissociation constant of the dilute solutions of rubidium soaps (caprylate, caprate, laurate and stearate) in water and alkanols (methanol, 1-butanol, l-pentanol, l-hexanol and l-octanol) have been determined by conductivity measurements at 35 ± 0.05°C. The dissociation constant increases with the dielectric constant of the solvent. The limiting equivalent conductance obtained from Debye-Huckel-Onsagar equation, Onsagar-Fuoss equation and Ostwald law are found to be in close agreement. The CMC values decrease with the increasing chain length of fatty acid constitutent of soap molecule but are found to be almost independent of the dielectric constant of the solvent.