Question

1: Decomposition of solid ammonium chloride is associated with____________ change.

Answer 1

It is associated with both chemical and physical change.
On heating strongly above 340 degree C, the white solid ammonium chloride, thermally decomposes into a mixture of two colourless gases ammonia and hydrogen chloride.
On cooling the reaction is reversed and solid ammonium chloride reforms.
This is an example of sublimation but here it involves both physical and chemical changes.