Answer
2 : 1
Explanation: -
To calculate the required mole ratio, the first step is writing the balanced chemical equation for the formation of Fe2O3 from Fe.
The balanced chemical equation for this reaction is
4 Fe + 3 O 2 --> 2 Fe2O3
Now from the balanced chemical equation we see
There are 4 moles of Fe and 2 moles of Fe2O3.
So their ratio is 4:2.
Simplifying by diving by 2, we get
The mole ratio between Fe and Fe2O3 is 2 : 1.