Physical Chemistry is the branch of chemistry which is quite like mathematics and physics in developing underlying principles of chemistry. It observes and explains the physical and chemical properties of matter. Physical chemistry at IIT JEE level starts from basics of mole concept, quantities at atomic level and covers energy, thermodynamics and kinetics which forms the basis of how reactions occur. Various topics covered in physical chemistry such as stoichiometry, chemical equilibrium, concentration of solutions, atomic structure, thermodynamics or chemical energetic form the backbone of chemistry at IIT JEE level and higher chemistry at graduate and post graduate level.
Physical chemistry has at least 30-40% weight-age in the IIT JEE chemistry paper and hence it is most important of the trio – physical, organic and inorganic chemistry.