Question

Find the value $b+c$ (sum of coefficients of reactants) from the given chemical equation:
$aFe+b{H}_{2}O\to cF{e}_3{O}_4+H_2$

• A. 6
• B. 5
• C. 4
• D. 7

Answer 1

The correct option is B 5

A chemical equation should be balanced to maintain the law of conservation of mass. That mean, on each side of the equation, equal number of atoms should be present. For the given reaction: $Fe+H_{2}O\to F{e}_3{O}_4+H_2$ ​

Number of Fe atoms on the $LHS=1$ ​

Number of Fe atoms on the $RHS=3$ ​

So we multiply Fe in LHS with 3​

Now, the number of O atoms on $LHS=1$​

Number of O atoms on the $RHS=4$ ​

So, we multiply $H_{2}O$ with 4​

Finally, number of atoms of H on $LHS=8$ ​

Number of H atoms on the $RHS=2$

So, we multiply $H_2$ by 4 ​

The final equation is $3Fe+4H_{2}O\to F{e}_3{O}_4+4H_2$ ​

Hence, $b+c=4+1=5$​