Identify the product 'X' obtained in the following chemical reaction: $CaCO_3 \xrightarrow{\Delta} X + CO_2$

According to the NCERT text, the thermal decomposition of calcium carbonate ($CaCO_3$, also known as limestone) on heating yields calcium oxide ($CaO$) and carbon dioxide ($CO_2$). The text explicitly states:

$$CaCO_3(s) \xrightarrow{\text{Heat}} CaO(s) + CO_2(g)$$

and mentions that 'Calcium oxide is called lime or quick lime.' Therefore, the product 'X' is quick lime (Option A).

• Option B (Gypsum) is incorrect because gypsum is a hydrated calcium sulphate ($CaSO_4 \cdot 2H_2O$), which is not formed in this reaction.
• Option C (Lime Stone) is incorrect because limestone is the reactant ($CaCO_3$) itself, not the product.
• Option D (Plaster of Paris) is incorrect because Plaster of Paris is calcium sulphate hemihydrate ($CaSO_4 \cdot \frac{1}{2}H_2O$), which is unrelated to the thermal decomposition of calcium carbonate.