Stability and Electrokinetic Potential of Aluminium Arsenate Sol

Aluminium arsenate sol has been prepared with a view to ascertaining whether any relationship exists between the stability and electrokinetic potential of the colloid. A correction for surface conductance effect, appreciable for slow rate of coagulation, has been applied by using an expression: \({1 \over \zeta_a} =\)\({1 \over \zeta} +\)\({m \over S}\) The true zeta potential for the rapid rate of coagulation is 11.5 mv and that for the slow rate is 17.6 mv, determined electro-osmotically. From electrophoresis the true zetapotential conies out to be 19.1 mv. A given rate of coagulation of the sol is characterised by a definite value of tree zeta-potential, indepen­dent, of the valency of the counter-ions used