Experiment 5: Synthesis of potassium tris (oxalato) ferrate (III) trihydrate
to synthesis potassium tris (oxalato) ferrate (III) trihydrate ,K3 [Fe (C2O4)3].3H2O.
Ferrous ammonium sulfate, Fe(NH4)2(SO4)2.6H2O is dissolved in a slightly acid solution, excess oxalic acid, H2C2O4, is added and the following reaction takes place: Fe(NH4)2(SO4)2.6H2O + H2C3O4 FeC2O4(s) + H2SO4 + (NH4)2SO4 + 6H2O FeC2O4 is finely divided precipitate and tends to be colloidal. However, heating the solution causes it to coagulate and facilitates separating the precipitate from the solution. Potassium oxalate is added to the FeC2O4 precipitate, which produces a slightly basic solution for the oxidation of the ferrous ion to the ferric ion, by hydroxide, H2O2. The following reaction takes place: H2O + HO2- +2Fe2+ 2Fe3+ + 3OH- The OH- ion concentration of the solution is high enough so that some of the Fe3+ reacts with OH- to form ferric hydroxide(brown precipitate) as follows: Fe3+ + 3OH- Fe(OH)3 With the addition of more H2C2O4, the Fe(OH)3 dissolves and the soluble complex K3[fe(c2o4)3].3h20 is formed according to : 3k2C2O4 + 2Fe(OH)3 + 3H2C2O4 2K3[Fe(c2o4)3].3H20 + 3h2o Ethanol is added to the solution to cause the complex iron salt to precipitate.
Data analysis and Discussion:
In this experiment, I have studied how to synthesis coordination compound. Coordination compounds are formed when a neutral metal atom: Fe acting as a Lewis acid, reacts with some neutral molecules, acting as Lewis bases; or when a metallic cation, acting as a Lewis acid, reacts with any of a variety of organic or inorganic molecules, cations, or anions, acting as Lewis bases. These Lewis bases: C2O4 and H2O are called ligands. (Lewis acids are electron pair acceptors and Lewis bases are electron pair donors. Ferrous ammonium solution is added with oxalic acid...