Comparative Study of Thermodynamic Parameters of Vanadium (IV) and (V) Acetohydroxamate Complexes

Acetohydroxamic acid, ch3conhoh, forms highly stable complexes with vanadium (v) and vanadium (iv) in 1:1, 1:2 and 1:3 mole ratios. the stability of these complexes can be determined in terms of thermodynamic parameters; ag,ah and as. the preliminary data, obtained through ph titration at various temperatures, was processed and analyzed by the computer program best for the refinement of graphically calculated log 0 values. graphs of ln/3 versus 1/t, gave a straight line, with a slope —ah/r and intercept as/r. enthalpy and free energy changes for v(v) complexes were found in the order of ml > ml2 > ml3 with a negative sign. whereas entropy change was found to be in the same order but positive, for vanadium (iv) acetohydroxamic acid complexes, the order of ag, ah and as was ml > ml3 > ml2. the as is most positive for a 1:1 complex, while ag and ah are more negative for the same.