This book has been written as per the syllabus prescribed by Sethu Institute of Technology (SIT), Virudhunagar for the First Semester of Engineering Chemistry students. The book has been developed in view of the recent development of the subject. The book covers important topics such as Ionic and Electrovalent bond, Covalent bond, Variable Valency, Coordinate or dative bond, Complex ions, Effects of Water on Rocks and Mineral, Boiler Troubles, Desalination of Water, Piezoelectric Materials, Shape Memory Alloys or Shape memory Polymers, Light Sensitive Materials, Goals, Significance and Basic Components of Green, Types of Dry Cells, Fuel Cells and Applications, Supercapacitors etc. have been explained in lucid manner. The book is sincerely offered to students and teaching fraternities associated with engineering chemistry from various engineering and technological institutions all over the country.