Question

On adding a drop of barium chloride solution to an aqueous solution of sodium sulfite, a white precipitate is obtained.

(a) Write a balanced chemical equation of the reaction involved

(b) What other names can be given to this precipitation reaction?

(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?

Answer 1

Reactions of Barium Chloride

1. (a) On adding a drop of Barium Chloride solution to an aqueous solution of Sodium Sulfite, Barium Sulfite is obtained which is a white color precipitate.
2. Reaction Involved: $\underset{\mathrm{Barium}\mathrm{Chloride}}{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{Sulfite}}{{\mathrm{Na}}_2{\mathrm{SO}}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Barium}\mathrm{Sulfite}}{{\mathrm{BaSO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Sodium}\mathrm{Chloride}}{2\mathrm{NaCl}\left(\mathrm{s}\right)}$
3. (B) The precipitation reaction is a double displacement reaction.
4. In this above reaction Barium replaces Sodium and Sodium replaces barium thus it is an example of a double displacement reaction.
5. (C) When we add dilute $\mathrm{HCl}$ to this reaction mixture Barium Chloride, Sulfur dioxide, and water are formed.
6. Barium Chloride is a Soluble substance that will make the white precipitate disappear.
7. Reaction involved: $\underset{\mathrm{Barium}\mathrm{Sulfite}}{{\mathrm{BaSO}}_3\left(\mathrm{s}\right)+}\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Barium}\mathrm{Chloride}}{{\mathrm{BaCl}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Sulfur}\mathrm{dioxide}}{{\mathrm{SO}}_2\left(\mathrm{l}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)}$

Therefore, Barium sulfite is obtained via a double displacement reaction.