Question

$FeC{r}_2{O}_4$ (chromite) is converted to Cr by following steps :
$Chromite\stackrel{I}{\to }N{a}_{2}Cr{O}_4\stackrel{II}{\to }C{r}_2{O}_3\stackrel{III}{\to }Cr$
I, II and III are

• A. $N{a}_{2}C{O}_3/air,\Delta ;C;C$
• B. $NaOH/air,\Delta ;C,\Delta ;Al,\Delta$
• C. $NaOH/air,\Delta ;C,\Delta ;Mg,\Delta$
• D. $conc.H_2{O}_2,\Delta ;N{H}_{4}Cl,\Delta ;;C,\Delta$

Answer 1

The correct option is B $NaOH/air,\Delta ;C,\Delta ;Al,\Delta$

Chromite $\left(FeC{r}_2{O}_4\right)$ reacts with $NaOH$ in the presence of air and heat to form $N{a}_{2}Cr{O}_4$ which reacts with coal in presence of heat to form chromium(III) oxide $\left(C{r}_2{O}_3\right)$.

$C{r}_2{O}_3$ reacts with $Al$ in presence of heat to form chromium $\left(Cr\right)$.

$FeC{r}_2{O}_4\stackrel{NaOH/air/Heat}{\to }N{a}_{2}Cr{O}_4\stackrel{C,heat}{\to }C{r}_2{O}_3\stackrel{Al/heat}{\to }Cr$

So answer is $B$.