Question

Balance the given chemical equation:

Al(s) + CuCl₂ (aq) → AlCl₃ (aq) + Cu(s)

Answer 1

Balanced equation: 2Al + 3CuCl₂→ 2AlCl₃ + 3Cu

Step 1: Write the unbalanced equation 

Al + CuCl₂→ AlCl₃ + Cu

Step 2: Compare the number of atoms of reactants with the number of atoms of products.

	Reactants (left side)	products (right side)
Element	Number of atoms	Number of atoms
Al	1	1
Cu	1	1
Cl	2	3

Step 3: Now, first we consider the element having unequal no. of atoms on both sides. Thus, first let us consider the chlorine atom. If we multiply 3 in the reactant (in CuCl₂) and 2 in the product (AlCl₃), we will get the equal number of atoms in both sides.

No. of atoms of chlorine	Reactant (in CuCl2)	Product (in AlCl3)
Initially	2	3
To balance	2 x 3 = 6	3 x 2 = 6

Step 4: Write the resulting equation:

Al + CuCl₂→ AlCl₃ + Cu

Step 5: Now check whether the equation is balanced or not by comparing the atoms

	Reactants (left side)	products (right side)
Element	Number of atoms	Number of atoms
Al	1	2
Cu	3	1
Cl	6	6

We find that the equation is not balanced yet. As the number of Cu and Al atoms are unequal on the two sides. First balance the Al atom.

Step 6: If we multiply 2 in the reactant (in Al), we will get the equal number of Al atoms on both sides.

No. of atoms of chlorine	Reactant (in Al)	Product (in 2AlCl3)
Initially	1	2
To balance	1 x 2 = 2	2

Step 7: Write the resulting equation:

2Al + 3CuCl₂→ 2AlCl₃ + Cu

Step 8: Now check whether the equation is balanced or not by comparing the atoms.

	Reactants (left side)	products (right side)
Element	Number of atoms	Number of atoms
Al	2	2
Cu	3	1
Cl	6	6

Step 9: Write the resulting equation:

2Al + 3CuCl₂→ 2AlCl₃ + Cu

We find that the equation is not balanced yet. As the number of copper atoms is unequal on the two sides.

Step 10: If we multiply 3 in the product (in Cu), we will get the equal number of atoms as in reactant (in CuCl₂)

No. of atoms of chlorine	Reactant (in 3CuCl2)	Product (in Cu)
Initially	3	1
To balance	3	1 x 3 = 3

Step 11: Write the resulting equation:

2Al + 3CuCl₂→ 2AlCl₃ + 3Cu

We find that the equation is balanced now.

Step 12: Write down the final balanced equation:

2Al + 3CuCl₂→ 2AlCl₃ + 3Cu