29. Cement is made hard with A.Dehydration B.Hydration and dissociation of water C.Dissociation of water D.Polymerisation
Answer: Option B Solution: Cements (e.g., Portland cement) harden because of hydration, chemical reactions that occur independently of the mixture’s water content; they can harden even underwater or when constantly exposed to wet weather. The chemical reaction that results when the anhydrous cement powder is mixed with water produces hydrates that are not watersoluble.
