This is the balanced chemical equation for the reaction between sodium carbonate $Na2CO3$ and hydrochloric acid $HCl$ to form sodium chloride $NaCl$, carbon dioxide $CO2$, and water $H2O$:

Na2CO3 + 2HCl → 2NaCl + CO2 + H2O

This equation shows that 1 mole of sodium carbonate reacts with 2 moles of hydrochloric acid to produce 2 moles of sodium chloride, 1 mole of carbon dioxide, and 1 mole of water.