Double Displacement Reaction Classification

This solution classifies the provided chemical reactions, identifying them as double displacement reactions based on ion exchange.

Reaction I: BaCl$_2$ and Na$_2$SO$_4$ Analysis

Reaction I involves the interaction between Barium Chloride (BaCl$_2$) and Sodium Sulfate (Na$_2$SO$_4$) in an aqueous solution.

• Reactants: $BaCl$_2$ (aq) and $Na$_2$SO$_4$ (aq).
• Ion Exchange: In solution, these ionic compounds dissociate into ions: Ba$^{2+}$, Cl$^-$, Na$^+$, and SO$_4^{2-}$. The cations and anions then switch their partners.
• Products Formed: Barium ions (Ba$^{2+}$) combine with sulfate ions (SO$_4^{2-}$) to form solid Barium Sulfate (BaSO$_4$). Sodium ions (Na$^+$) combine with chloride ions (Cl$^-$) to form soluble Sodium Chloride (NaCl).
• Classification: This process, where ions of the reactants are exchanged, is defined as a double displacement reaction. The formation of insoluble BaSO$_4$ also makes it a precipitation reaction.

The chemical equation is: $BaCl$_2$ (aq) + Na$_2$SO$_4$ (aq) → BaSO$_4$ (s) + 2NaCl (aq)$

Reaction II: Pb(NO$_3$)$_2$ and KI Analysis

Reaction II describes the reaction between Lead(II) Nitrate (Pb(NO$_3$)$_2$) and Potassium Iodide (KI) in an aqueous medium.

• Reactants: $Pb(NO$_3$)$_2$ (aq) and $KI$ (aq).
• Ion Exchange: Dissociation yields Pb$^{2+}$, NO$_3^-$, K$^+$, and I$^-$ ions. These ions subsequently exchange partners.
• Products Formed: Lead(II) ions (Pb$^{2+}$) react with iodide ions (I$^-$) to yield solid Lead(II) Iodide (PbI$_2$). Potassium ions (K$^+$) combine with nitrate ions (NO$_3^-$) forming soluble Potassium Nitrate (KNO$_3$).
• Classification: Similar to Reaction I, this reaction involves the swapping of ions between the two compounds, classifying it as a double displacement reaction. The production of solid PbI$_2$ identifies it as a precipitation reaction.

The chemical equation is: $Pb(NO$_3$)$_2$ (aq) + 2KI (aq) → PbI$_2$ (s) + 2KNO$_3$(aq)$

Final Reaction Classification Summary

Both Reaction I and Reaction II clearly demonstrate the characteristics of double displacement reactions. This involves the mutual exchange of ions between two ionic compounds dissolved in water. Therefore, both reactions are classified as double displacement reactions.