Question

Heating of ammonium chloride solution is a (This question has multiple correct answers):
(a)- Physical change
(b)- Chemical change
(c)- Depends on temperature
(d)- Can’t say

Answer 1

Hint: The ammonium chloride is converted into ammonia and hydrogen chloride when heated. When the gases are cooled they reform white ammonium chloride.

Complete step by step answer:
If its physical form (solid, liquid, or gas) changes from one form to another then it is a physical change. If the reactants are converted into products then it is a chemical change. If the reaction gives different products at different temperatures then the reaction depends on the temperature.
Ammonium chloride is a chemical compound whose formula is $N{{H}_{4}}Cl$.
When the solution of ammonium chloride is heated it forms ammonia and hydrogen chloride.
The reaction is given below:
$N{{H}_{4}}Cl(s)\rightleftharpoons N{{H}_{3}}(g)+HCl(g)$
So, in this reaction when the ammonium chloride or solution of ammonium chloride is strongly heated above the temperature of ${{340}^{\circ }}C$, the white solid ammonium chloride is converted into two gases ammonia and hydrogen chloride.
Since the solid form is converted into gas, hence it is a physical change.
When both the gases are cooled down then they reform the solid ammonium chloride. This means that the bonds are breaking and joining in the process to form products. Hence, it is a chemical process also.

Hence, the correct options are (a)- Physical change and (b)- Chemical change.

Note: This reaction is an example of a sublimation reaction in which the solid is directly converted into gases. It is a reversible reaction. The heating of ammonium chloride is an endothermic reaction.