When sodium carbonate (Na2CO3) and calcium chloride (CaCl2) react in aqueous solution, a precipitation reaction occurs, resulting in the formation of solid particles. The color of these solid particles is white.

The chemical equation for this reaction is:

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

In this reaction, sodium carbonate and calcium chloride react to form calcium carbonate (CaCO3) and sodium chloride (NaCl). Calcium carbonate is a white, insoluble compound that precipitates out of the solution as solid particles. The remaining sodium chloride stays dissolved in the solution.

Therefore, the color of solid particles formed by the reaction of sodium carbonate and calcium chloride is white.