Lime materials — properties of quicklime (CaO) Which statements correctly describe quicklime used in construction materials and chemical processes?

Introduction / Context:Quicklime (calcium oxide) is a key material for soil stabilization, mortar production, and environmental applications. Knowing its origin and behavior is crucial for safe handling and effective use at site.

Given Data / Assumptions:

• Limestone is primarily CaCO3.
• Calcination occurs in kilns at elevated temperatures.
• Quicklime reacts exothermically with water to form slaked lime (Ca(OH)2).

Concept / Approach:Calcination drives CO2 off limestone, producing CaO. The product is highly reactive with water and atmospheric moisture, which is why storage must be dry and airtight. Quicklime is generally non-crystalline (amorphous) as produced industrially, contributing to its reactivity.

Step-by-Step Solution:Calcination: CaCO3 → CaO + CO2 (endothermic decomposition).Hygroscopic behavior: CaO readily hydrates → Ca(OH)2 with substantial heat release.Material structure: commonly amorphous/finely crystalline, aiding rapid reaction.Therefore, all three statements are correct.

Verification / Alternative check:Industrial datasheets list loss on ignition, free CaO content, and storage precautions due to moisture affinity.

Why Other Options Are Wrong:The extra option claiming pre-hydrated and non-reactive contradicts the very definition of quicklime; pre-hydrated material is slaked lime, not quicklime.

Common Pitfalls:Exposing quicklime to ambient humidity leading to unsafe heat release; mistaking hydrated lime for quicklime in mix designs; ignoring purity effects on performance.

Final Answer:All of the above