Which of the following is an example of double displacement reaction?

Correct option is D

The correct answer is (D)  $$Na_2SO_4 (aq) +$$ $$BaCl_2$$​ → $$BaSO_4$$ (s)  + 2NaCl (s)

• The reaction $$Na_2SO_4 + BaCl_2$$ → $$BaSO_4$$ + 2NaCl is an example of double displacement reaction.
  

Information booster:

A double displacement reaction occurs when two compounds exchange their ions to form two new compounds.

• In this reaction:
  • The sodium ion (N$$a^+$$​) from sodium sulfate (Na2SO4Na_2SO_4
    ​$$Na_2SO_4$$​) combines with the chloride ion (Cl−Cl^-$$Cl^-)$$​ from barium chloride ($$BaCl_2$$​BaCl2BaCl_2) to form sodium chloride (NaClNaClNaCl).
  • The sulfate ion ($$SO_4^2-$$​SO42−SO_4^{2-}
    ​) from sodium sulfate combines with the barium ion ($$Ba^2+$$​Ba2+Ba^{2+}
    ) from barium chloride to form barium sulfate (BaSO4BaSO_4
    ​$$BaSO_4$$​).

The products of the reaction are sodium chloride (NaCl) and barium sulfate (BaS$$O_4$$​).

General Formula:

The general form of a double displacement reaction is:

$$AX+BY\to AY+BX$$

Here:

• A and B are positively charged ions (cations).
• X and Y are negatively charged ions (anions).

Key Features:

• One of the products, like BaSO4BaSO_4$$BaSO_4$$​, often forms a precipitate or is insoluble.
• This reaction is typically observed in aqueous solutions.