What happens to ammonium chloride upon heating and cooling?
When ammonium chloride is heated, it undergoes thermal decomposition, breaking down into ammonia gas and hydrogen chloride gas. The reaction can be represented by the following chemical equation:
NH4Cl(s) → NH3(g) + HCl(g)
Upon cooling, the ammonia and hydrogen chloride gases will recombine to form ammonium chloride again, resulting in the formation of white fumes.