Question

Describethe preparation of potassium dichromate from iron chromite ore.

What isthe effect of increasing pH on a solution of potassium dichromate?

Answer 1

Potassiumdichromate is prepared from chromite oreinthe following steps.

Step(1): Preparation of sodium chromate

Step(2): Conversion of sodium chromate intosodium dichromate

Step(3):Conversion of sodium dichromate to potassium dichromate

Potassiumchloride being less soluble than sodium chloride is obtained in theform of orange coloured crystals and can be removed by filtration.

Thedichromate ion existsin equilibrium with chromate ionat pH 4. However, by changing the pH, they can be interconverted.