 Aprotic solvents are neutral, chemically inert substances such as benzene and chloroform.They have a low dielectric constant, do not react with either acids or bases and therefore do not favor ionization.The fact that picric acid gives a colorless solution in benzene which becomes yellow on adding aniline shows that picric acid is not dissociated in benzene solution and also that in the presence of the base aniline it functions as an acid, the development of yellow color being due to formation of the picrate ion.