A classic example of a double displacement reaction is when sodium carbonate (Na2CO3) reacts with calcium chloride (CaCl2) to form calcium carbonate (CaCO3) and sodium chloride (NaCl). In this reaction, the cations (calcium and sodium) essentially “swap” places, resulting in the formation of two new compounds.
Explanation:
Reactants: Na2CO3 (aq) + CaCl2 (aq)
Products: CaCO3 (s) + 2NaCl (aq)
Key points about double displacement reactions:
Ion exchange:
The key characteristic of a double displacement reaction is the exchange of ions between the reacting compounds.
Aqueous solutions:
Most double displacement reactions occur in aqueous solutions, meaning the reactants are dissolved in water.
Precipitate formation:
Sometimes, a solid precipitate forms as a product of the reaction. In the example above, calcium carbonate is insoluble in water and precipitates out as a solid.
For a more helpful explanation to multiple-choice questions, try including the answer options in your search.