Dr Mehrotra has enunciated the chemical theory of indicators, apart from suggesting the applicability of universal type of indicators with both acidic and basic functions. In the field of redox titration, he has extended the applicability of ceramic salts and of hypobromites in the estimation of a large number of organic and inorganic constituents. He has made a detailed study of alkoxides and carboxylates of a number of elements. This work is now being extended to the corresponding sulphur analogues and also to organometallic derivatives.