The process by which a substance absorbs moisture on exposure to the atmosphere is called? A) Deliquescence B) Efflorescence C) Dehydrogenation D) Desalination Related MCQs: The process by which a substance absorbs moisture upon exposure to the atmosphere is called? Which layer of the atmosphere is mainly responsible for weather process? On Mollier chart free expansion, or throttling process from high pressure to atmosphere is represented by Gradual exposure to actual feared situation is called: