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How the potassium dicharomate prepared from chrome iron ore? |
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Answer» Solution :Preparation of `K_(2)Cr_(2)O_(7)` from chrome iron orecomposition of chromite ore is `FeO.Cr_(2)O_(3)`. Step I : Concentration of ore : Powdered ore is concentrated by washing with current of WATER in hydraulic CLASSIFIER. Step II. Roasting : Conversion of chromite ore into sodium chromate : `{:(4FeO.Cr_(2)O_(3) +O_(2)rarr 2Fe_(2)O_(3)+4Cr_(2)O_(3)),([2Cr_(2)O_(3)+4Na_(2)CO_(3)+3O_(2)rarr4Na_(2)CrO_(4)+4CO_(4)+4CO_(2)]xx2),(barul(4FeOCr_(2)O_(3)+8Na_(2)CO_(3)+7O_(2) rarr 2Fe_(2)O_(3)+8Na_(2)CrO_(4)+8CO_(2))):}` Step III : Conversion of `Na_(2)CrO_(4)` into `Na_(2)Cr_(2)O_(7)` `2Na_(2)CrO_(4)+H_(2)SO_(4)" (conc.)" rarrNa_(2)Cr_(2)O_(7)+Na_(2)SO_(4)+H_(2)O` Step IV : Conversion of `Na_(2)Cr_(2)O_(7)` to `K_(2)Cr_(2)O_(7)` `Na_(2)Cr_(2)O_(7)+2KCL rarr K_(2)Cr_(2)O_(7)+2NaCl` The solution is concentrated and hot solution is orange red crystals and `NaCl` remains in the solution. `K_(2)Cr_(2)O_(7)` is filtered and purified. |
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