Question

Balance the following chemical reaction:
$Zn(s)+PbC{{l}_{2}}(aq)\to Pb(s)+ZnC{{l}_{2}}(aq)$
a.) $Zn(s)+PbC{{l}_{2}}(aq)\to Pb(s)+ZnC{{l}_{2}}(aq)$
b.) $2Zn(s)+PbC{{l}_{2}}(aq)\to Pb(s)+2ZnC{{l}_{2}}(aq)$
c.) $Zn(s)+2PbC{{l}_{2}}(aq)\to Pb(s)+ZnC{{l}_{2}}(aq)$
d.) $Zn(s)+2PbC{{l}_{2}}(aq)\to Pb(s)+2ZnC{{l}_{2}}(aq)$

Answer 1

Hint: Number of atoms of each element should be equal on both sides of the equation. As per the law of conservation of mass, the number of atoms of each element in an equation should be equal on both sides of the equation.
The correct option is option A.

Complete answer:
Therefore, a balanced equation is the type of chemical equation one which has the same number of atoms of each element on both sides.
The reaction in the above question is:
$Zn(s)+PbC{{l}_{2}}(aq)\to Pb(s)+ZnC{{l}_{2}}(aq)$
The number of atoms of $Zn$ on the left is 1 and on the right side of the equation of the equation the number of zinc atoms is 1.
Therefore, there is no need to balance the zinc element as it is balanced.
The number of atoms of $Pb$on the left side of the equation is 1 and on the right side of the equation also the number of $Pb$ atoms is 1.
Therefore, there is no need to balance the lead element as it is balanced.
The number of atoms of $Cl$ on the left side of the equation is 2 and on the right side of equation also the number of $Cl$ atoms is 2.
Therefore, there is no need to balance the chlorine element as it is already balanced.
All the three elements present in the reaction are balanced on both the sides therefore; the above reaction is already a balanced equation therefore; option A is the correct answer.
Option A is : $Zn(s)+PbC{{l}_{2}}(aq)\to Pb(s)+ZnC{{l}_{2}}(aq)$

Note:
Law of conservation of mass is applied in balancing an equation. A balanced equation is one which has a number of atoms of each element on both sides.