Question

What would you observe when crystals of Washing soda when exposed to air. Name the phenomenon exhibited?

Answer 1

• Efflorescence is the property of some substances to lose wholly or partly, their water of crystallization when their crystals are exposed to dry air even for a short time. They become powdery. Such substances are called efflorescent substances. They lose their water of crystallization and thus their crystalline shape and become powdery when exposed to air.
• When hydrated Sodium carbonate is exposed to dry air, it becomes a monohydrate.
• Na₂CO₃.10H₂O (s)$\stackrel{\mathrm{Dry}\mathrm{air}}{\to }$ Na₂CO_{3 .}H₂O(s) + 9H₂O.(v)