Question

sodium carbonate does undergoes thermal decomposition , why?

Answer 1

As sodium occupies high position in the metal reactivity series, it when combined with carbonate ions, forms very strong and stable bond (with the carbonate ions). This strong and stable bond between sodium and carbonate ions resist decomposition upto very high tempertaure and requires lot of heat energy to completely decompose. Such high temperatures and heat energy is not provided by normal heating. Thus sodium carbonate does not decompose on normal heating. Sodium Carbonate starts to decompose above 500 degree celsius. Anhydrous sodium carbonate melts at 851 degree celsuis, to yield sodium oxide and carbon di oxide

Anhydrous sodium carbonate melts at 851°C :

Na2CO3(s) ---->CO2(g) + Na2O(s)