YU  Dianying

Abstract: In accordance with conductivity being one of the additive properties in dilute solution of electrolyte and the equilibrium principle of ionization of weak acid, One can derive an equation relating concentration with conductivity. If k<10^-4 (equilibrium constant for ionization reaction) the concent ration of a weak acid is directly proportional to the square of conductivity. C/C^o is therefore substituted by  (x_t/x₀）² in the kinetic equation for dissolving the acid into pure water and so we can derive the relation  ln[1- (x_t/x₀）² ]= -kt,expressed in specific conductivity x. Data x and t have been .measured under the stationary state and the straight 1ines are obtained by plotting ln[1- (x_t/x₀）² ]= -kt against t. This shows the correctness of the equations derived. The experiment shows also that in addition to the factors such as temperature etc.,the dissolving rate constant k of the acid is related to the surface area of solid.

Keywords: ionization,the surface area of solid,weak acid