Lime chemistry — correct chemical formula of quicklime (burnt lime) Identify the correct chemical formula for quicklime used in construction and industry:

Introduction / Context:
Lime products are central to many construction processes: mortars, plasters, soil stabilization, and environmental applications. Distinguishing between limestone, quicklime, and slaked lime is essential.

Given Data / Assumptions:

• Limestone (raw) is calcium carbonate.
• Calcination removes carbon dioxide to produce quicklime.
• Hydration converts quicklime to slaked lime.

Concept / Approach:
The reactions are: CaCO3 (limestone) → CaO (quicklime) + CO2 (on heating); and CaO + H2O → Ca(OH)2 (slaked lime). Therefore quicklime is calcium oxide, formula CaO.

Step-by-Step Solution:
Recognize raw material: CaCO3.Apply calcination: CaCO3 → CaO + CO2.Identify product: CaO is quicklime.

Verification / Alternative check:
Material safety data and standards list quicklime as calcium oxide, confirming the selection.

Why Other Options Are Wrong:
CaCO3 is limestone. CO3CO2 is not a valid formula. None is incorrect because CaO fits exactly.

Common Pitfalls:
Confusing slaked lime Ca(OH)2 with quicklime CaO; improper handling of CaO can cause burns due to its exothermic hydration.

Final Answer:
CaO