Question

Which of the following is not a balanced equation?

• A. $\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$
• B. $\mathrm{Mg}+{\mathrm{CuSO}}_4\to {\mathrm{MgSO}}_4+\mathrm{Cu}$
• C. $\mathrm{NaOH}+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$
• D. $\mathrm{Zn}+\mathrm{S}\to \mathrm{ZnS}$

Answer 1

The correct option is A

$\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$

The explanation for the correct option

(A) $\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$

Balanced Equation

On both sides of a balanced chemical equation, there is the same number of atoms of each element.

In the equation $\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$, the number of $\mathrm{Cl}$ atoms is not the same on both sides of the equation.

Hence, $\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$ is not a balanced equation.

The explanation for the incorrect options

(B) $\mathrm{Mg}+{\mathrm{CuSO}}_4\to {\mathrm{MgSO}}_4+\mathrm{Cu}$

Here the number of magnesium $\left(\mathrm{Mg}\right)$, copper $\left(\mathrm{Cu}\right)$, sulfur $\left(\mathrm{S}\right)$ and oxygen $\left(\mathrm{O}\right)$ atoms are the same on both sides of the equation, so it is a balanced equation.

(C) $\mathrm{NaOH}+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$

Here, the number of sodium $\left(\mathrm{Na}\right)$, oxygen, hydrogen $\left(\mathrm{H}\right)$ and chlorine $\left(\mathrm{Cl}\right)$ atoms is the same on both sides of the equation, so it is a balanced equation.

(D) $\mathrm{Zn}+\mathrm{S}\to \mathrm{ZnS}$

In this reaction, the number of zinc $\left(\mathrm{Zn}\right)$ and sulfur $\left(\mathrm{S}\right)$ atoms is the same on both sides of the equation, so it is also a balanced equation.

Therefore, the equation $\mathrm{Fe}+{\mathrm{Cl}}_2\to {\mathrm{FeCl}}_3$ is not a balanced equation, and option (A) is the correct option.