Iron reacts with atmospheric oxygen to form iron oxide or ferric oxide. Look at the chemical equation for this reaction:

[tex]\[ Fe + O_2 \rightarrow Fe_2O_3 \][/tex]

This equation is unbalanced. Which of the following is the correct balanced equation for this reaction?

A. [tex]\[ 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

B. [tex]\[ 3 Fe + 4 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

C. [tex]\[ 2 Fe + 4 O_2 \rightarrow 3 Fe_2O_3 \][/tex]

D. [tex]\[ 3 Fe + 3 O_2 \rightarrow 4 Fe_2O_3 \][/tex]

E. [tex]\[ 4 Fe + 4 O_2 \rightarrow 3 Fe_2O_3 \][/tex]



Answer :

To balance the chemical equation for the reaction between iron (Fe) and oxygen (O₂) to form iron oxide (Fe₂O₃), we need to ensure that the number of atoms of each element is the same on both the reactant and product sides of the equation.

The unbalanced equation is:
[tex]\[ \text{Fe} + \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3 \][/tex]

Let's balance the equation step by step:

1. Write down the number of atoms of each element on both sides of the equation:
- Reactants:
- Fe: 1
- O: 2
- Products:
- Fe: 2
- O: 3

2. Balance the iron (Fe) atoms first:
To balance Fe, we need the same number of Fe atoms on both sides. We have 2 Fe atoms in Fe₂O₃ on the product side, so we need 2 Fe atoms on the reactant side:
[tex]\[ 2 \text{Fe} + \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3 \][/tex]

3. Balance the oxygen (O) atoms:
We have 2 oxygen atoms on the reactant side (from O₂) and 3 oxygen atoms on the product side (from Fe₂O₃). To balance the O atoms, we need to find a common multiple of 2 and 3, which is 6.
- We need 3 O₂ molecules to have 6 O atoms on the reactant side:
[tex]\[ 2 \text{Fe} + 3 \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3 \][/tex]

4. Re-check the Fe atoms:
After balancing the O atoms, the Fe atoms might need adjustment. We have 2 Fe atoms on the reactant side, and 2 Fe atoms in Fe₂O₃ on the product side. To balance the equation completely:
- Double the Fe on the reactant side to match with two Fe₂O₃ on the product side:
[tex]\[ 4 \text{Fe} + 3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3 \][/tex]

Now, our balanced equation is:
[tex]\[ 4 \text{Fe} + 3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3 \][/tex]

Thus, the correct balanced equation is:

A. \(4 \text{Fe} +3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3\)

So, the answer is Option A.