The Author of this Book, Dr. Bal Raj Deshwal, has been teaching Chemistry in All India Jat Heroes’ Memorial College, Rohtak since 1996. Dr. Deshwal received gold medal in M.Sc. Chemistry from M D University, Rohtak. He obtained his Ph.D. in Thermodynamics, one of the pioneer fields of Physical Chemistry. He was awarded Brain Pool Fellowship by Scientific Exchange Program in collaboration with Korean Federation of Science and Technology Societies, S. Korea (KOFST). He was invited as visiting scientist in Korean Institute of Energy Research, Daejeon, S. Korea where he worked for 3 years. He was also invited as visiting professor in Madrid University, Spain, Warsaw University of Technology, Poland. He has published two international patents, and 54 research papers in journals of international and national repute. He has also authored two books namely “Comprehensive Engineering Chemistry” and “Water Chemistry and Environmental Science”. He has also supervised Ph.D. and M.Phil. students.