$Na_2SO_4 + BaCl_2 \rightarrow 2NaCl + BaSO_4$ The above reaction is:

Question

Accepted Answer

The correct option is (2):

The reaction given, $Na_2SO_4 + BaCl_2 ightarrow 2NaCl + BaSO_4$, is a classic example of a double displacement reaction. In this type of reaction, the ions of two different ionic compounds exchange places, forming two new compounds. Here, sodium sulfate ($Na_2SO_4$) and barium chloride ($BaCl_2$) react. The sodium ions ($Na^+$) from sodium sulfate combine with the chloride ions ($Cl^-$) from barium chloride to form sodium chloride ($NaCl$), while the barium ions ($Ba^{2+}$) from barium chloride combine with the sulfate ions ($SO_4^{2-}$) from sodium sulfate to form barium sulfate ($BaSO_4$). A key characteristic of many double displacement reactions, including this one, is the formation of a precipitate. Barium sulfate ($BaSO_4$) is an insoluble compound, meaning it will precipitate out of the solution. This exchange of ionic partners is the defining feature that classifies it as a double displacement reaction.

The incorrect option is (1):
A displacement reaction involves one element displacing another element from a compound. For example, $Zn + CuSO\_4 \rightarrow ZnSO\_4 + Cu$. In our given reaction, there are no free elements, but rather two compounds reacting, and both compounds are undergoing a change in their partners.

The incorrect option is (3):
A decomposition reaction is one where a single compound breaks down into two or more simpler substances, usually with the input of energy (like heat or light). An example would be the decomposition of calcium carbonate: $CaCO\_3 \rightarrow CaO + CO\_2$. The reaction in question involves two reactants forming two new products, which is not a breakdown of a single compound.

The incorrect option is (4):
Since only one of the options (Double displacement) correctly describes the given reaction, the option "All of the above" is incorrect. The reaction cannot be simultaneously a displacement, double displacement, and decomposition reaction, as these are distinct types of chemical reactions.