Give an example of a double displacement reaction other than the one given in Activity 1.10.
An example of a double displacement reaction is the reaction between lead(II) nitrate and potassium iodide solutions. When these solutions are mixed, a yellow precipitate of lead(II) iodide is formed.
The balanced chemical equation for this reaction is: Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq)
This is a double displacement reaction because there is an exchange of ions between the reactants. The lead ions (Pb²⁺) combine with iodide ions (I⁻) to form the insoluble precipitate of lead(II) iodide, while potassium ions (K⁺) combine with nitrate ions (NO₃⁻) to form potassium nitrate which remains in the solution.
Explanation
The textbook context mentions Activity 1.2 where solutions of lead(II) nitrate and potassium iodide are mixed, forming a precipitate. The context defines double displacement reactions as those 'in which there is an exchange of ions between the reactants.' Since Activity 1.10 (involving BaSO₄ formation) is already given as an example, Activity 1.2 provides another valid example where ions are exchanged between lead(II) nitrate and potassium iodide, resulting in the formation of lead(II) iodide precipitate and potassium nitrate in solution.