Question

In chromite ore, the oxidation number of iron and chromium are respectively

• A. +3, + 2
• B. +3, +6
• C. +2, + 6
• D. +2, + 3

Answer 1

Answer: (D)

Chromite or chrome iron ore is $FeC{r}_2{O}_4$ . Its actual composition is $FeO.C{r}_2{O}_3$ . In $\text{FeO}$ , oxidation state of Fe is calculated as $x+(-2)=0$ $x=+2$ Similarly, in $C{r}_2{O}_3,$ the oxidation state of Cr is calculated as $2\times x+(-2)\times 3=0$ $2x=+6$ $x=+3$