The solid product of the reaction between solutions of calcium chloride (CaCl₂) and sodium carbonate (Na₂CO₃) is calcium carbonate (CaCO₃).

Here's the balanced chemical equation for the reaction:

CaCl₂(aq) + Na₂CO₃(aq) → CaCO₃(s) + 2NaCl(aq)

This is a double displacement reaction where the calcium ions (Ca²⁺) from calcium chloride combine with the carbonate ions (CO₃²⁻) from sodium carbonate to form the insoluble calcium carbonate. This solid precipitates out of the solution, making it the solid product of the reaction.