ABSTRACT
Chemical kinetics is the study of expressions to determine the rate of a reaction. The central idea of the collision theory is the requirement of appropriate collision between reactants. The mechanism must represent as close as possible the actual geometries of reactants, intermediates, transition states, and products. The mechanism indicates how the reactants approach to react by forming the transition state, yielding the products through the flux of electrons, bond breaking, and bond formation. In 1884 van’t Hoff found an expression for the temperature dependence of the equilibrium constant which greatly influenced Arrhenius to discover another expression for temperature dependence of the rate constant in 1889. In 1935, H. Eyring, M. G. Evans, and M. Polanyi, improved the transition state theory, independently by introducing partition functions in the reaction rate equation. Some metals nickel, copper, platinum, palladium are used as catalysts in hydrogenation of alkenes and alkynes.
