Question

Mixing two colorless aqueous solutions results in the formation of white precipitate. Write a chemical reaction in agreement with the above observation.

Answer 1

Double Displacement reaction: When two aqueous solutions are mixed together, after exchange of ions new compounds are formed. An insoluble solid known as precipitate is also formed during this reaction.

Precipitate: An insoluble solid formed during chemical reaction between two aqueous solutions.

Mixing two colorless aqueous solutions i.e. Barium chloride $\left({\mathrm{BaCl}}_2\right)$ and Sodium sulphate $\left({\mathrm{Na}}_2{\mathrm{SO}}_4\right)$, we will get white precipitate of Barium sulphate $\left({\mathrm{BaSO}}_4\right)$ and aqueous solution of sodium chloride $\left(\mathrm{NaCl}\right)$.

The chemical reaction for the statement is:

$\underset{(\mathrm{Barium}\mathrm{chloride})}{\underbrace{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}}+\underset{(\mathrm{Sodium}\mathrm{sulphate})}{\underbrace{{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}}\to \underset{\underset{(\mathrm{White}\mathrm{precipitate})}{\underbrace{(\mathrm{Barium}\mathrm{sulphate})}}}{\underbrace{{\mathrm{BaSO}}_4\left(\mathrm{s}\right)}}+\underset{(\mathrm{Sodium}\mathrm{chloride})}{\underbrace{2\mathrm{NaCl}\left(\mathrm{aq}\right)}}$