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  1. conical flask
  2. test tube
  3. beaker
  4. glass rod


  1. Conc. HCL
  2. ethyl alcohol
  3. Potassium perocyanide.
  4. conc. H2SO4


                    Iron filing on heating with dil. H2SO4 in air oxidizes to ferric sulphate Ferric sulphate when mixed with potassium Ferrocyanide gives blue colored Prussian blue complex in presence of H2SO4.

HCl + HNO3 → NACl + 2H2O + 2[Cl]

Fe + 3[Cl] →   FeCL3

4FeCL3 + 3K4 [Fe (CN) 6] →Fe4 [Fe (CN) 6] + 12 NACl

FeSO4 + K4 [Fe (CN) 6] →Fe2 [Fe (CN) 6] + K2SO4

FeSO4 + H2SO4 → FeSO4 + H2

2 Fe (SO4)3 + 3K4 [Fe (CN) 6] →Fe4 [Fe (CN) 6]3 + 6H2SO4 + 2H2O


  0.5 gram of iron filing was taken in a beaker. Firstly all the required apparatus were cleaned and 2 drops of HCL and 6 drops of HNO3 was added in a test tube called aqua regia. Then, iron filing was dissolved in aqua regia. The reaction was carried out very slowly and stringed with a glass rod and after complete dissolution of iron filings, the solution was added and the solution was changed into deep blue color. Then ½ test tube of ethyl alcohol was added slowly without disturbing the solution. The solution was left for a day and ppt of Prussian was obtained.


            Prussian blue Fe4 [Fe (CN) 6] is prepared in lab by using K4 [Fe (CN) 6] in the solution of iron filing and aqua regia.


                            Hence, Prussian blue can be prepared in lab by using K4 [Fe (CN) 6]


  1. Apparatus should be handled with care.
  2. Apparatus should be cleaned before and after use.

       3.  Ethyl alcohol should be added slowly from the wall of conical flask without disturbing the solution.

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