PREPARATION OF SODIUM TRIOXALATO FERRATE (III) Na3 [Fe(C2O4)3 ]. 9H2O.

TO PREPARATION OF SODIUM TRIOXALATO FERRATE (III) Na3 [Fe(C2O4)3 ]. 9H2O.

Theory:

 The action of sodium oxalate on hydrated ferric oxide can be used to prepare sodium trioxalato ferrite (III) in the laboratory. The solution of ferric chloride is treated with sodium hydroxide to obtain a precipitate of hydrated ferric oxide. It is then treated with a hot solution of sodium oxalate. Any insoluble impurities are removed by filtration and the solution is concentrated. It is slowly cooled to obtain a green crystal of sodium trioxalato ferrate Na3 [Fe(C2O4)3 ]. 9H2O.

Chemical Required :

• Ferric chloride = 10.0 g 
• Sodium hydroxide = 11.5 g
• Oxalic acid =12.9g

Chemical Equations :

FeCl3 + 3NaOH    →  Fe(OH3)  +  3NaCl 

2NaOH   + (COOH)2     →   (COONa)2  +  2H2O 

2Fe(OH)3   +     6(COONa)2    →     2Na3{Fe(C2O4)3}  +   6 NaOH

Procedure:

• Dissolve 10.0 g of Ferric Chloride in 10.0 ml of water and 7.5 g of sodium hydroxide in 50.0 ml of water
• Add sodium hydroxide solution to the Ferric chloride solution in small lots with stirring to get a precipitate of Ferric hydroxide Fe(OH3) . 
• Separate the precipitate of ferric hydroxide from the butcher funnel and wash the precipitate with hot water.
• Dissolve 12.0 g of oxalic acid in 50.0 ml of water in a beaker and add 4.0 g of sodium hydroxide pellets to obtain a sodium oxalate solution. Stir ferric hydroxide precipitate in hot sodium oxalate solution with a glass rod.
• Filter the solution to remove any insoluble impurities. Concentrate the green coloured filter on the china dish at the crystallization point.
• Allow the concentrated solution to cool slowly to obtain crystals of sodium trioxylate ferrite. Wash the crystals with cold water and dry it.
•  Note the weight and colour.

Result: 

• Colour of crystals = green
• yield      g
• Expected yield = 15.0 g.

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