What Happens When Na2so4 Is Heated?

When Na2SO4 is heated, it undergoes a series of chemical changes. The first change occurs at about 400°C when the compound melts and water of crystallization is removed, forming anhydrous Na2SO4.

As the temperature increases further, an exothermic decomposition reaction takes place between 500-600°C, resulting in the formation of sodium sulfide (Na2S) and sulfur trioxide (SO3) gases:

2Na2SO4(s) → 2Na2S(s) + 3O2(g) + 2SO3(g)

The sodium sulfide can react with atmospheric oxygen to form sodium sulfate (Na2SO4) and sulfur dioxide (SO2):

2Na2S(s) + 3O2(g) → 2Na2SO4(s) + 2SO2(g)

Overall, heating Na2SO4 causes it to lose water of crystallization and undergo thermal decomposition, forming sodium sulfide and sulfur trioxide gases.