ON THE THEORY OF WASHING AND EXTRACTION

Abstract

When precipitates are washed with a definite quantity of water or some other solvent, it's not recommended to use the washings at the same time. The principle also applies to the extraction between two liquid phases. In almost all analytical textbooks this principle is introduced with the next formula : [numerical formula] In some of them such special numbers, for instance, as n=4 and 5 are put in the formula to show C_5 < C_4 practically. But the authors thought this is not the best way for the advanced students and tried to give a proof of C_<n+1> <C_n.