Which one of the following equations is the balanced chemical equation for the given reaction ?
$\text{Fe + H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4\text{ + H}_2$
$ ext{Fe + 4H}_2 ext{O} ightarrow ext{Fe}_3 ext{O}_4 ext{ + H}_2$
$ ext{3Fe + H}_2 ext{O} ightarrow ext{Fe}_3 ext{O}_4 ext{ + 2H}_2$
$ ext{3Fe + 4H}_2 ext{O} ightarrow ext{Fe}_3 ext{O}_4 ext{ + 4H}_2$
$ ext{3Fe + 4H}_2 ext{O} ightarrow ext{Fe}_3 ext{O}_4 ext{ + H}_2$
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-2 – 2023
1. Balance Fe: There are 3 Fe atoms on the right (in Fe3O4) and 1 on the left. Multiply Fe on the left by 3: 3Fe + H2O $\rightarrow$ Fe3O4 + H2.
2. Balance O: There are 4 O atoms on the right (in Fe3O4) and 1 on the left (in H2O). Multiply H2O on the left by 4: 3Fe + 4H2O $\rightarrow$ Fe3O4 + H2.
3. Balance H: Now there are 4 * 2 = 8 H atoms on the left. There are 2 H atoms on the right (in H2). Multiply H2 on the right by 4: 3Fe + 4H2O $\rightarrow$ Fe3O4 + 4H2.
Left side: Fe = 3, H = 4 * 2 = 8, O = 4 * 1 = 4
Right side: Fe = 3, H = 4 * 2 = 8, O = 4
The number of atoms of each element is equal on both sides.