Distinctive relationships between the rest potential and the hole injection rate observed for electroless dissolution of n-GaAs and n-GaP are reported. The results are explained on the basis of a kinetic model including anodic decomposition, thermal electron excitation, and recombination. It is shown that significant information concerning the mechanisms of anodic dissolution and of electron-hole recombination can be obtained from a study of the dependence of the rest potential on the hole injection rate.