JAMB - Chemistry (1979 - No. 14)

When ammonium, potassium and calcium carbonates are each separately heated

none of them will decompose

each of them will decompose to give carbondioxide and the respective oxide

ammonium carbonate and potassium carbonate will not decompose

only ammonium carbonate and the respective oxide

ammonium carbonate will decompose to give carbondioxide, water and ammonia

Solid ammonium carbonate decomposes as it is heated.

(NH4)2CO3 → 2 NH3 + CO2 + H2O