abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy derivatives and their corresponding radical species .the salvation calculations were carried out using the b3lyp/6-31g(d,p) method .acceptable linear correlation were found between the experimental oxidation potentials . and the eigenvalues of somo and homo, as well as the calculated electrode oxidation potentials , of the studied n- hydroxy molecules . the values of regression analyses were found to be 0.90,0.93 and 0.89 respectively . such linear relationships may be used as a tool to predict the physical properties of n- hydroxy compounds without having to synthesize them. part two: this section deals with structural determination with comparative oxidation states method. with the help of this method we can determine structure of all kinds of molecule from very simple to very complicate .comparative oxidation states method can also helps us to obtain different types of bonding in the molecules ,bond order, shape, polarity and many other property in the molecules this method has many advantages such as simplicity and rapidity compared to styx or lewis method.