This book is specially designed for B.Sc. Chemistry Honours Degree students. However, it is believed to be helpful to post-graduate students also. It covers by and large physical chemistry part of the Chemistry Honours syllabus taught in different Indian Universities. Elaborate and lucid discussion of each chapter is the strength of this book. Questions and numerical problems are also included at the end of almost every chapter. Strenuous effort has been given to derive different mathematical equations as well as to handle quantum mechanics using mathematics taught in undergraduate level. The book contains 20 chapters, covering the following topics: - Thermodynamics is thoroughly discussed in this book, covering 1st law, 2nd law and 3rd law of thermodynamics, their applications, thermochemistry and its applications. Applications of thermodynamics in different areas like refrigerators, compressors, power plants, IC engines etc. are also discussed. Statistical thermodynamics is also discussed elaborately. - Chemical kinetics is another important part of chemistry since it covers reaction rate, order of a reaction, theory behind the reaction rate etc. Catalyst is also an important aspect since it has profound influence on reaction rate. Type of catalyst and mechanism of different catalyzed reactions are discussed in detail. A chemical reaction reaches an equilibrium state if carried out in a closed container. However, the equilibrium is sufficiently influenced by other parameters, like pressure, temperature etc. - Different physical states of matter (gaseous state, liquid state and solid state). In the solid state behavior of conductors and semiconductors are discussed thoroughly using quantum mechanics. - Detailed discussion of electrochemistry, electrochemical cell and ionic equilibria is another important aspect of this book. Application of thermodynamics in electrochemical cell is also discussed. Concept of buffer solutions, pH and indicators are discussed in detail. - Phase equilibria is another important part of physical chemistry. The chapter includes details of phase rule, phase diagram, applications, different types of heterogeneous equilibrium system etc. - Colligative properties of dilute solutions are well documented, covering, Henry's law, Raoult's law of lowering of vapour pressure, elevation of boiling point, depression of freezing point, osmotic pressure etc. - Surface chemistry and properties of colloidal solutions are very much important in different chemical industries. These two sections are well discussed in this book. It includes details of derivation of different laws, theories behind the adsorption, stability of colloidal solutions etc. - Nuclear reactions are different from chemical reactions and energy, related to nuclear reactions is enormous, much higher than any chemical reaction. Study of different nuclear reactions including natural radioactivity, artificial radioactivity etc. and kinetics of nuclear reactions are well discussed in this book. Different areas of applications of nuclear reactions are also covered in this book. - Another important aspect of chemical reactions is chemical bonding. The book covers details of covalent bonding including quantum numbers, overlapping of atomic orbitals, molecular orbitals. Besides that ionic bonding and other types of bonding are also discussed in detail. - Photochemical reactions are different from chemical reactions. Light energy is the main source of photochemical reactions. Details of it including photochemical laws, mechanism etc. are well documented in this book.