Engineering Chemistry: Principles and Industrial Applications provides a clear and practical understanding of essential chemical concepts used in engineering and industry. The book covers water treatment, electrochemistry, corrosion, batteries, fuel cells, fuels, polymers, smart materials, phase rule, lubricants, cement, biosensors, and modern spectroscopic techniques. It combines fundamental principles with numerical problems, industrial processes, engineering applications, and emerging technologies such as green hydrogen, biodegradable polymers, and advanced sensing methods. Designed for engineering students, the book supports both academic learning and practical understanding of chemistry in technological and industrial systems.