This summary analyzes recurring patterns in NEET questions from INC-03.
Highest-Frequency NEET Topics in Groups 16-18:
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Xenon Fluoride Geometry (XeF2, XeF4): NEET asks the shape/hybridization of XeF2 (linear, sp3d — NOT angular) and XeF4 (square planar, sp3d2 — NOT tetrahedral) repeatedly. The key trap: "number of bonds does NOT predict geometry when lone pairs are present." XeF2 with 2 bonds is linear (not bent), because 3 lone pairs occupy equatorial positions. Expect 1 question every 2-3 years specifically on Xe compound geometry.
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Contact Process — Oleum Formation: NEET frequently asks WHY SO3 is not dissolved in water directly (acid mist) and what the intermediate oleum is. The question "in the Contact process, SO3 is absorbed in _____ to form _____" is a recurring fill-in-the-blank type. Expect 1 question every 2-3 years.
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Oxoacid Strength Comparison: Arranging HOCl, HClO2, HClO3, HClO4 in increasing/decreasing order, or explaining why HClO4 is the strongest (more oxygens, better conjugate base stabilization). This appears regularly in both straightforward and assertion-reason formats.
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HF as Weak Acid — Reasoning: The counterintuitive fact that the most electronegative element gives the weakest acid is a classic NEET conceptual question. Know both reasons: (a) H-F bond strength 568 kJ/mol, (b) intermolecular hydrogen bonding.
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V2O5 Catalyst at 450°C: Identification of catalyst type and temperature for Contact process Step 2. Distractors include Pt, Fe2O3, 800°C, and 250°C. The "unit" to memorize is "V2O5 at 450°C" as a package.
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Interhalogen Shapes: Matching ClF3 → T-shaped, BrF5 → square pyramidal, IF7 → pentagonal bipyramidal is tested in table-completion and matching-type questions.
Strategy: 70% of NEET marks from this chapter come from Xe compound geometry + Contact process. Master these two areas before anything else.