Physical Chemistry has an important role in making Chemistry an exact science. It can be said exaggeration that Physical Chemistry is best understood when the technique to solve problems is understood. This book is an attempt made by the author towards that end. In general, students give little attention to solving problems. The author has seen many students spending more time and effort in trying to avoid solving problems than in learning to solve them. Needless to say, the ability to solve problems comes with earnest practise.