Barium chloride $+$Aluminium sulfate$\to$Barium sulfate$+$Aluminum chloride. Write the balanced equation for the above chemical reactions.

Balancing a chemical reaction:

1. A chemical equation represents a chemical reaction symbolically, with the reactants and products represented by their corresponding chemical formulas.
2. To balance a chemical reaction we first need to write an unbalanced equation for the reaction
3. Now, we have to count the number of elements except hydrogen and oxygen present on the left-hand side and right-hand side and balance them.
4. At last we have to balance hydrogen and oxygen atoms because they are present in more than one compound.

The reaction of barium chloride and aluminum sulfate:

1. Barium chloride reacts with aluminum sulfate to produce barium sulfate as a precipitate and aluminum chloride.
2. The unbalanced equation for the reaction is $\underset{\mathrm{Barium}\mathrm{chloride}}{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Aluminum}\mathrm{sulfate}}{{\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Aluminum}\mathrm{chloride}}{{\mathrm{AlCl}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Barium}\mathrm{sulfate}}{{\mathrm{BaSO}}_4\left(\mathrm{s}\right)}$
3. Balancing barium, aluminum, chlorine, and sulfur atoms we get, $\underset{\mathrm{Barium}\mathrm{chloride}}{3{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Aluminum}\mathrm{sulfate}}{{\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Aluminum}\mathrm{chloride}}{2{\mathrm{AlCl}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Barium}\mathrm{sulfate}}{3{\mathrm{BaSO}}_4\left(\mathrm{s}\right)}$
4. Oxygen is automatically balanced.

Therefore, the balanced equation for the reaction of Barium chloride $+$Aluminum sulfate$\to$Barium sulfate$+$Aluminum chloride is $\underset{\mathrm{Barium}\mathrm{chloride}}{3{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Aluminum}\mathrm{sulfate}}{{\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Aluminum}\mathrm{chloride}}{2{\mathrm{AlCl}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Barium}\mathrm{sulfate}}{3{\mathrm{BaSO}}_4\left(\mathrm{s}\right)}$