Question

Balance the following reaction.
$Zn\left(s\right)+Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+Zn{Cl}_2\left(aq\right)$

• A. $Zn\left(s\right)+Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+Zn{Cl}_2\left(aq\right)$
• B. $2Zn\left(s\right)+Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+2Zn{Cl}_2\left(aq\right)$
• C. $Zn\left(s\right)+2Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+Zn{Cl}_2\left(aq\right)$
• D. $Zn\left(s\right)+2Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+2Zn{Cl}_2\left(aq\right)$

Answer 1

The correct option is A $Zn\left(s\right)+Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+Zn{Cl}_2\left(aq\right)$

The unbalanced redox equation is as follows:
$Zn\left(s\right)+Pb{Cl}_2\left(aq\right)⟶Pb\left(s\right)+Zn{Cl}_2\left(aq\right)$
All atoms other than H and O are balanced.
The oxidation number of Zn changes from 0 to +2. The change in the oxidation number of Zn is 2.
The oxidation number of Pb changes from +2 to 0. The change in the oxidation number of Pb is 2.
The increase in the oxidation number is balanced.
Thus, the chemical equation is already balanced.