Calcium Oxide, Calcium Carbonate, Plaster of Paris — Predicted 2026
AI-Predicted Question Angles for UPSC 2026
Stoichiometry of Hydrates
highNEET often tests the understanding of water of crystallization. A question might involve calculating the mass of water lost when a certain amount of gypsum is converted to Plaster of Paris, or the amount of water required to set a given mass of Plaster of Paris. This requires precise knowledge of the formulas CaSO$_4 cdot 2$H$_2$O and CaSO$_4 cdot rac{1}{2}$H$_2$O and their molar masses.
Effect of Heating Conditions
highThe impact of different heating temperatures on gypsum is a classic NEET question. Distinguishing between the formation of Plaster of Paris ($100^circ ext{C}$) and dead burnt plaster (above $200^circ ext{C}$) and explaining why dead burnt plaster loses its setting property is a strong candidate for conceptual questions. This tests not just recall but also a deeper understanding of chemical changes.
Interconversion Reactions and Industrial Processes
mediumQuestions might involve a sequence of reactions, for example, starting from limestone, converting it to quicklime, then to slaked lime, and then back to calcium carbonate. Understanding the industrial preparation of quicklime (calcination) and the laboratory preparation of calcium carbonate from slaked lime are key. This tests the overall understanding of the chemical relationships between these compounds.
Role of Calcium Compounds in Environmental Chemistry
lowWhile less frequent, questions could touch upon the environmental applications, such as quicklime's use in neutralizing acidic industrial wastes or its role in flue gas desulfurization. This would require linking the basic properties of CaO to real-world environmental solutions, adding an interdisciplinary touch.