Coexistence curves of the binary mixture isobutyric acid–water with added ions (K+, Cl−)

Measurement of the coexistence curve of the binary mixture isobutyric acid–water (I–W) with increasing amounts of ions impurity showed essentially a linear dependence of the critical temperature and critical composition with concentration of (K+,Cl−) ions. Each coexistence curve of the electrolyte mixture is characterized by a new effective critical exponent β=(0.251−0.771) is neither compatible with the Ising value β=0.325. The experimental technique used here is the visual method.