Chemistry
Ammonium chloride is also a sublimable solid. Give a reason why sublimation of ammonium chloride involves a physical & a chemical change.
Answer
Ammonium chloride [NH4Cl] sublimes on heating and dissociates into ammonia [NH3] & hydrogen chloride [HCl], which recombine on cooling to give back NH4Cl again. As the change is reversible, hence, it is a physical change.
NH4Cl [s] ⇌ NH3 [g]+ HCl [g]
Dissociation of ammonium chloride involves formation of new products, hence it is a chemical change. Therefore, sublimation of ammonium chloride involves both – a physical and a chemical change.
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