Question

The equivalent mass of $\mathrm{Fe}$ in $\mathrm{FeO}$ is $(\mathrm{Fe}=56)$

• A. $56$
• B. $28$
• C. $36$
• D. $18.66$

Answer 1

The correct option is B

$28$

Explanation:

Step 1: Equivalent mass:

• Equivalent mass is equal to the molecular/atomic mass divided by the number of electrons involved in the reaction per molecule/atom/ion.

Step 2: Formula for equivalent mass:

$\mathrm{Equivalent}\mathrm{mass}\mathrm{of}\mathrm{Element}=\frac{\mathrm{Atomic}\mathrm{mass}\mathrm{of}\mathrm{element}}{\mathrm{Valency}}$

Step 3: Calculation of Equivalent mass:

• The valency of iron$\left(\mathrm{Fe}\right)$ in Iron oxide $\left(\mathrm{FeO}\right)$ is $+2$.
• The atomic mass of Iron is $56$.
• Thus, the equivalent mass of iron is:

$$\begin{gathered} \mathrm{Equivalent}\mathrm{mass}\mathrm{of}\mathrm{Fe}=\frac{\mathrm{Atomic}\mathrm{mass}\mathrm{of}\mathrm{Fe}}{\mathrm{Valency}} \\ \mathrm{Equivalent}\mathrm{mass}\mathrm{of}\mathrm{Fe}=\frac{56}{2}=28 \end{gathered}$$

Hence, the correct option is B. The equivalent mass of $\mathrm{Fe}$ in $\mathrm{FeO}$ is $\mathbf{28}$.