Question

Write the equation for the action of heat on: Ammonium chloride
State whether the reaction is an example of thermal decomposition or thermal dissociation.

Answer 1

We have to know that Arrhenius is one of the concepts for acid and bases. Swedish chemist Arrhenius is the world's first chemist to talk about acid and bases. Depending on his concept and limitations later so many concepts are developed. Even Arrhenius is the birthplace of the concept of acids and bases. Followed by Arrhenius chemist the concept of acids and bases discuss Bronsted and Lowry in the world.

Complete answer:
We have to remember that the molecular formula of ammonium chloride is ${\text{N}}{{\text{H}}_{\text{4}}}{\text{Cl}}$.
Ammonia is react hydrochloric acid to give ammonium chloride as salt. If heated, it gives ammonium chloride and forms a product of ammonia and hydrochloric acid. So, it is a reversible reaction in chemistry.
The reaction of ammonium chloride is given below,
${\text{N}}{{\text{H}}_{\text{4}}}{\text{Cl}} \to {\text{HCl + N}}{{\text{H}}_{\text{3}}}$
${\text{HCl + N}}{{\text{H}}_{\text{3}}} \to {\text{N}}{{\text{H}}_{\text{4}}}{\text{Cl}}$
${\text{N}}{{\text{H}}_{\text{4}}}{\text{Cl}} \rightleftarrows {\text{HCl + N}}{{\text{H}}_{\text{3}}}$
In the above reaction the action of heat on ammonium chloride is an example of thermal dissociation. Because from ammonium chloride, it dissociates to form ammonia and hydrochloric acid.
Hence, the action of heat on ammonium chloride is an example of thermal dissociation. This reaction is not an example of thermal decomposition.

Note:
We must remember that the hydrochloric acid (${\text{HCl}}$) is an acid in the Arrhenius concept. According to the Arrhenius concept one substance said to acid means, acid is nothing but a substance that dissociates to give hydrogen ion when decomposed in the water. Ammonia is a base in the Bronsted and Lowry concept. According to Bronsted and Lowry concept one substance said to base means, bases is nothing but a substance that has and is able to donate lone pairs of electrons. Ammonium chloride is inorganic salt.