Effect of buffers and ionic strength on the stability constant of complexes of iron(III) with salicylic acid and its derivatives

摘要

The 1 :1 complex formed by iron(III) with salicylic acid and its seven derivatives were studied by spectrophotometry and the effect of phthalate-HCl and KCl-HCl buffers on the value of stability constants of 1 :1 complex determined by spectrophotometry,was evaluated.The thermodynamic value of stability constant of each system was determined by obtaining the values at different ionic strength and extrapolating them to zero ionic strength.For extrapolation,a new approach was made which gives a straight line curve making it easier to extrapolate at zero ionic strength to get the thermodynamic value thus reducing the uncertainty in extrapolation.