Which of the following is a product of first step and is used as reactant in next step for manufacture of $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ from concentrated chromite ore ?

• A

  Sodium dichromate
• B

  Potassium chromate
• C

  Sodium sulphate
• Correct answer
  D

  Sodium chromate

Solution

(1) Conversion of chromite ore into sodium chromate
(2) Conversion of sodium chromate into sodium dichromate
(3) Conversion of sodium dicbromate to potassium dichromate $\underset{\text { Sod. dichromate }}{\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}+2 \mathrm{KCl} \longrightarrow \underset{\text { Pot. dicbromate }}{\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}+2 \mathrm{NaCl}$

Hence, the correct answer is option: 'D'.