Question

salt which undergoes thermal dissociation on heating??

Answer 1

here's your answer

Ammonium chloride undergoes thermal dissociation on heating .

Answer 2

ammonium nitrate and ammonium nitrite as both are highly unstable. ammonium nitrate decomposes into nitrous oxide(N2O) and water on heating.
ammonium nitrite decomposes to nitrogen and water.
both cannot be used for producing ammonia by reaction with alkalis.