Question

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution :

(A) Exchange of atoms takes place

(B) Exchange of ions takes place

(C) A precipitate is produced

(D) An insoluble salt is produced.

The correct option is :

• A. (B) and (D)
• B. (A) and (C)
• C. only (B)
• D. (B), (C) and (D)

Answer 1

The correct option is D

(B), (C) and (D)

Explanation:

Double displacement reaction:

• When two compounds react, positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products is known as a double displacement reaction.
• A double replacement reaction is represented by the general equation, $\mathrm{AB}+\mathrm{CD}\to \mathrm{AD}+\mathrm{CB}$
• When Sodium sulphate(${\mathrm{Na}}_2{\mathrm{SO}}_4$) reacts with Barium chloride solution (${\mathrm{BaCl}}_2$), a white precipitate of Barium sulphate(${\mathrm{BaSO}}_4$) and Sodium chloride$\left(\mathrm{NaCl}\right)$ are formed.

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

• In the above reaction, the exchange of chloride and sulphate ions takes place and an insoluble precipitate ${\mathrm{BaSO}}_4$ is formed.

Hence, option (D) is the correct answer.