When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallized from the solution. When compound (C) is treated with , orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
The compounds A, B, C and D are given as under:
Following are the reactions :