Based on detailed analysis of last 5 years' papers. Perfect for 2026 Boards prep!
| Question Example | Type/Marks | Years Repeated | Notes |
|---|---|---|---|
| Calculate spin-only magnetic moment for Fe²⁺ (d⁶, 4 unpaired e⁻). Is it paramagnetic? | Numerical (2 marks) | 2021 Term 2, 2022, 2023, 2024, 2025 | Repeated 5x; μ ≈ 4.9 BM. |
| Why do transition metals show variable oxidation states? Element with max states in 3d series? | Short Answer (2 marks) | 2022, 2023, 2024, 2025 | Repeated 4x; Mn (+2 to +7). |
| Explain KMnO₄ as oxidizing agent in acidic medium. Reaction with Fe²⁺/oxalic acid (balanced eq.). | Reasoning/Equation (3 marks) | 2021 Term 1, 2022, 2023, 2025 | Repeated 4x; MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺. |
| What is lanthanoid contraction? Two consequences (e.g., similar radii Zr-Hf, basicity decrease). | Short Answer (3 marks) | 2022, 2023, 2024, 2025 | Repeated 4x; Poor 4f shielding. |
| Compare K₂Cr₂O₇ and KMnO₄ as oxidants. Reaction with KI in acidic medium. | Comparison (2 marks) | 2023, 2024, 2025 | Repeated 3x; Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺. |
| Assertion: Sc³⁺ is colorless while Ti³⁺ is colored. Reason: d⁰ vs d¹ configuration. | Assertion-Reason (1 mark) | 2022, 2024, 2025 | Repeated 3x; d-d transition. |
| Why are transition metals good catalysts? Example (e.g., Fe in Haber, V in Contact). | Reasoning (2 marks) | 2021 Term 2, 2023 | Repeated 2x; Variable states. |
| Compare lanthanoids and actinoids (oxidation states, size, reactivity). | Short Answer (2 marks) | 2024, 2025 | Repeated 2x; Actinoids more reactive. |
| MCQ: Magnetic nature of [Cu²⁺] (d⁹): (a) Diamagnetic (b) Paramagnetic. | MCQ (1 mark) | 2023, 2025 | Repeated 2x; (b). |
| Case-based: Explain color in d-block ions. Calculate μ for Ni²⁺ (d⁸, 2 unpaired). | Case-Based (4 marks) | 2022, 2025 | Repeated 2x; μ ≈ 2.83 BM. |
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