10.22376/ijpbs.2019.10.1.p1-12 Volume 1 Issue 2 2010 (April - June) The conductance of s-acetylthiocholine halides and perchlorate has been measured in ethanol – water mixtures (28.6 lessThan D lessThan 72.0). The conductance parameters derived from Fuoss – Onsager conductance theory indicate that the solvation of halides and perchlorate decreases with the decrease of the dielectric constants until a certain minimum and then increases again. The plot of log kA vs. 1/D is found to be non linear indicating that the equation of association cannot be applied. The association constant is analyzed using the solvent separated – ion pair model.  lessThan br / greaterThan lessThan br / greaterThan N. H. El – Hammamy,A. I. Kawana,M. F. Amira,N. S. Elsisy conductivity, s-acetylthiocholine, ion pair. -