ABC26IN0193 · Main Group Elements
Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Exam: CSIR-NET 2014 · Marks: 2 · Difficulty: Easy
Chromite ore on fusion with sodium carbonate gives
(a)$\mathrm{Na_2CrO_4}$ and $\mathrm{Fe_2O_3}$
(b)$\mathrm{Na_2Cr_2O_7}$ and $\mathrm{Fe_2O_3}$
(c)$\mathrm{Cr_2(CO_3)_3}$ and $\mathrm{Fe(OH)_3}$
(d)$\mathrm{Na}_{2} \mathrm{CrO}_{4}$ and $\mathrm{Fe}_{2}\left(\mathrm{CO}_{3}\right)_{3}$
Answer
Explanation
Chromium is extracted from chromite ore: \[ \text{(I)}\quad 4\mathrm{FeCr_2O_4} + 8\mathrm{Na_2CO_3} + 7\mathrm{O_2} \rightarrow 8\mathrm{Na_2CrO_4} + 2\mathrm{Fe_2O_2} + 8\mathrm{CO_2} \]
\[ \text{(II)}\quad 2\mathrm{Na_2CrO_4} + \mathrm{H_2SO_4} \rightarrow \mathrm{Na_2SO_4} + \mathrm{Na_2Cr_2O_7} + \mathrm{H_2O} \]
\[ \text{(III)}\quad \mathrm{Na_2C_2O_7} + 2\mathrm{C} \rightarrow \mathrm{Cr_2O_7} + \mathrm{Na_2CO_3} + \mathrm{CO} \]
\[ \text{(IV)}\quad \mathrm{Cr_2O_3} + 2\mathrm{Al} \rightarrow \mathrm{Al_2O_3} + 2\mathrm{Cr} \]
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