Discussion on Mr. Chatterjee's Paper pH & its Application to Waterworks Practice:Hydrogen on Concentration and Water Purification Practice

During the past few years there has been an increasing recognition of the role played by small variations in acidity or alkalinity in many reactions which are of great technical importance. Such considerable is the effect produced by a small variation in acidity or alkalinity that the terms 'slightly acid' or 'slightly alkaline' have been rendered vague without real meaning and hence the fundamental importance of hydrogen-ion concentration which is nothing but the intensity of term for acidity or alkalinity as opposed to quantity term has been fully realised. Thus hydrogen-ion concentration is of fundamental importance in processes which involve the proteins, such as manufacture of artificial milk foods, leather tanning, manufacture of glue and gelatin, wool and silk industries. By a careful adjustment of hydrogen-ion concentration, many of the defects of the soil can be remedied, water can be softened, sugar juices can be purified, metallic hydroxides and certain insoluble salts can be separated, sludges can be precipitated, colloidal emulsions can be broken down, colloidal suspensions of clay can be flocculated, electroplating can be efficiently carried out, pure metals electrolytically deposited and many operations which depend upon interfacial forces can be made satisfactory.