Elimination and Addition reactions are a group of the chemical reactions that have extensive applications in the synthesis of organic compounds. In these reactions, usually two or more species are combined together, and if the reactants are asymmetrical, two or more products are produced, which mainly one of the products is stable thermodynamically or kinetically in compare with others and is introduced as the main product or preferred product. Determination of the thermodynamic stability of chemical compounds and the prediction of preferred reaction product is one of the favorable subjects of theoretical chemists. This matter is done in density functional theory (DFT) [1] by quantum indicators such as electronic chemical potential [2], absolute chemical hardness and softness [3], molecular polarization and absolute electrophilicity[4]. The main purpose of this project is to determine that with which the above indicators and which definitions of these indicators, can predicted and describe the quantitative distribution of the products of the mentioned reactions and, consequently, the main route of the process with more appropriately. The obtained result show that almost in all cases, the hardnesses and global electrophilicities with corresponding maximum hardness principle (MHP) and minimum electrophilicity principle (MEP) respectively, can predict the major product of both addition and elimination reactions correctly.
