Question

The oxidation number of iron in $F{e_3}{O_4}$ is :
A.$ + 2$
B.$ + 3$
C.$\dfrac{8}{3}$
D.$\dfrac{2}{3}$

Answer 1

Hint: We know the most common oxidation state of oxygen which is $ - 2$ and the overall compound is neutral . So , the sum of charges of iron and oxygen is zero . This is how we will calculate the oxidation state of iron .

Complete Step by step answer: Let us first find out what oxidation state means.
Oxidation State : oxidation state of an element in a particular compound can be defined as the charge acquired by its atom on the basis of electronegative character from other atoms in the molecule. Initially we will have to find out the oxidation state of the oxygen atoms in the compound and then the total oxidation state should made to zero and calculate the oxidation state of Iron.
Oxidation state of oxygen is known . We just have to find out the oxidation state of iron .
The oxidation state shown by oxygen is $ - 2$. The number of oxygen atoms is $4$. The number of iron atoms is $3$.
Let the oxidation state of iron in this compound be $x$ .
The overall charge on the compound is zero . So we have-
$
  3x + 4( - 2) = 0 \\
  3x = 8 \\
  x = \dfrac{8}{3} \\
 $
This is the calculated oxidation state of iron in this compound .

Hence, the correct option is C .

Note: It should be noted that Iron shows variable oxidation states which leads to confusion for most of the students so while calculating the oxidation number it should be assumed that it may have different oxidation numbers. The oxidation state of any element depends on its electronic shell configuration and the other element to which it is being added.