Sodium carbonate reacts with sulphuric acid. The resultant products can be confirmed by: 

Acids react with metal carbonates to form salt and water with the evolution of carbon dioxide gas. The best approach to check for CO2 is through "lime water," a diluted calcium hydroxide solution. Chalk or limestone is the solid calcium carbonate precipitate that is created when carbon dioxide is bubbled through the solution. A Milky white color solution is seen.