Question

Potassium dichromate is prepared from

• A. Chromate obtained by the fusion of chromite ore with sodium carbonate in free access of air
• B. Pyrolusite which is fused with potassium hydroxide in the presence of air
• C. Iron pyrite by the fusion with potassium carbonate in presence of moisture
• D. None of these

Answer 1

Answer: (A)

Chromate obtained by the fusion of chromite ore with sodium carbonate in free access of air

Answer 2

: $\underset{Chromiteore}{4FeCr_{2}O_{4}} + 8Na_{2}CO_{3} + 7O_{2} \rightarrow \underset{\begin{aligned} & Sodiumchromate \ & (yellow) \end{aligned}}{8Na_{2}CrO_{4}}$$$+ 2Fe_{2}O_{3} + 8CO_{2}$$

}{Na_{2}Cr_{2}O_{7} + 2KCl \rightarrow \underset{\begin{aligned} & Potassium \\ & dichromate \end{aligned}}{K_{2}Cr_{2}O_{7}} + 2NaCl}$$