89. Solving a chemistry problem

4. Calculate the value of the ξ-potential at the boundary of the collodion membrane - an aqueous solution of KCl, if, when this solution is forced through the membrane under a pressure of 26.6 * 103 Pa, the flow potential E turned out to be 8.8 * 10-3V; specific electrical conductivity of the medium χ \u003d 1.3 * 10-2 Sm * m-1, dielectric constant ε \u003d 81, electrical constant ε0 \u003d 8.85 * 10-12 F / m, viscosity η \u003d 1 * 10- 3 Pa*s.