Gas Evolution Reactions: CO32−

Begin by writing a skeletal equation that includes the reactants and products that form when the cation of each reactant combines with the anion of the other.

HNO3(aq) + Na2CO3(aq) → H2CO3(aq) + NaNO3(aq)

You must recognize that H2CO3(aq) decomposes into H2O(l) and CO2(g) and write the corresponding equation.

HNO3(aq) + Na2CO3(aq) → H2O(l) + CO2(g) + NaNO3(aq)

Finally, balance the equation.

2 HNO3(aq) + Na2CO3(aq)

→ H2O(l) + CO2(g) + 2 NaNO3(aq)