This document describes Thermodynamic formulation of activated complextheory, Lindemann – Hinshelwood mechanism ofunimolecular reactions. London- Eyring-Polanyimethod of calculation of energy of activation. Application of activated complex theory of reactionrates. Temperature dependence of pre-exponentialfactor. Thermodynamic aspects of reaction rates. Unimolecular reactions and its validityThermodynamic formulation of activated complextheory, Lindemann – Hinshelwood mechanism ofunimolecular reactions. London- Eyring-Polanyimethod of calculation of energy of activation. Application of activated complex theory of reactionrates. Temperature dependence of pre-exponentialfactor. Thermodynamic aspects of re