CaCl2(aq) + (NH4)2CO3(aq) → CaCO3(s) + 2NH4Cl(aq
The Correct Answer and Explanation is:
Balanced Chemical Equation:
CaCl₂(aq) + (NH₄)₂CO₃(aq) → CaCO₃(s) + 2NH₄Cl(aq)
Explanation
This is a classic example of a double displacement reaction, also known as a precipitation reaction because a solid (precipitate) forms from the mixing of two aqueous solutions.
Let us begin by understanding the chemical components:
- CaCl₂ is calcium chloride, a soluble ionic compound that dissociates into Ca²⁺ and Cl⁻ ions in water.
- (NH₄)₂CO₃ is ammonium carbonate, another soluble ionic compound that dissociates into NH₄⁺ and CO₃²⁻ ions.
- When these two solutions are mixed, the calcium ions (Ca²⁺) from calcium chloride react with the carbonate ions (CO₃²⁻) from ammonium carbonate to form calcium carbonate (CaCO₃), which is an insoluble compound. Therefore, it precipitates out of solution as a solid.
- The remaining ions, NH₄⁺ and Cl⁻, stay dissolved in water and form ammonium chloride (NH₄Cl), which remains in the aqueous phase.
Now let us confirm that the equation is balanced:
- On the left side, we have:
- 1 calcium atom
- 2 chlorine atoms
- 2 ammonium (NH₄⁺) ions
- 1 carbonate ion
- On the right side, we have:
- 1 calcium atom in calcium carbonate
- 1 carbonate ion in calcium carbonate
- 2 ammonium ions in 2 NH₄Cl
- 2 chlorine atoms in 2 NH₄Cl
Thus, the number of each type of atom is equal on both sides, meaning the equation is balanced correctly.
In summary, this chemical reaction demonstrates how ionic compounds in solution can exchange ions and form a precipitate. The formation of calcium carbonate solid is the key observable evidence of the reaction taking place.
