Question

Balance the following equation.

\[\ce{Calcium chloride + Sulphuric acid -> Calcium sulphate + Hydrogen chloride}\]

Answer 1

Step 1: Write the chemical equation from the given word equation.

\[\ce{CaCl2 + H2SO4 -> CaSO4 + HCl}\]

Step 2: Write the number of atoms of each element in the unbalanced on both sides of the equation.

Element	Number of atoms in reactants	Number of atoms in products
Ca	1	1
Cl	2	1
H	2	1
S	1	1
O	4	4

Step 3: In the given equation H₂SO₄ is a compound and contains hydrogen elements. On the left-hand side there are two hydrogen atoms and on the right side one hydrogen atom. Equalise H atoms on both sides.

Hydrogen atoms	In reactants (H2SO4)	In products (HCl)
Initially	2	1
To balance	2	2 × 1

To equalise the number of hydrogen atoms we use 2 as the factor in the product so that the number of H atoms on both sides is equal. Therefore, the equation becomes

\[\ce{CaCl2 + H2SO4 -> CaSO4 + 2HCl}\]

Now, count the atoms of each element on both sides of the equation. The number of atoms on both sides is equal hence, the balanced equation is

\[\ce{CaCl2 + H2SO4 -> CaSO4 + 2HCl}\]