Science – Hard Level – GK Questions

Appel reaction: R-OH + SOCl₂/PPh₃ → R-Cl + SO₂ + POCl₃. Converts alcohols to alkyl chlorides under mild conditions. Important synthetic method in organic chemistry. [[NCERT Chemistry Class 12]]

Qubit (quantum bit) can exist in superposition (0 and 1 simultaneously), enabling parallel computation. Entanglement allows correlated qubit states. Potential to solve problems intractable for classical computers. [[NITI Aayog Reports]]

Dead Cas9 (dCas9) fused with activators/repressors can regulate gene expression without DNA cleavage (CRISPRa/i). Standard Cas9 cuts DNA for editing. This versatility expands therapeutic applications. [[DBT Reports, NCERT Biology Class 12]]

Δx·Δp ≥ h/4π: fundamental limit in quantum mechanics, not due to measurement errors. Highlights probabilistic nature of microscopic world. [[NCERT Physics Class 12]]

AI trained on biased data may discriminate in hiring, lending, policing. Ethical AI requires fairness, transparency, accountability. Emerging topic for governance sections. [[NITI Aayog Principles for Responsible AI]]

t₁/₂ = 0.693/k for first-order reactions. Unlike zero/second-order, it doesn't depend on [A]₀. Useful for radioactive decay calculations. [[NCERT Chemistry Class 12]]

Square planar [Pt(NH₃)₂Cl₂] shows cis-trans isomerism. Tetrahedral/octahedral symmetric complexes don't. Important for stereochemistry in coordination compounds. [[NCERT Chemistry Class 12]]

Tollens' test: Aldehydes reduce [Ag(NH₃)₂]⁺ to metallic silver (silver mirror); ketones don't react. Classic test for carbonyl compounds. [[NCERT Chemistry Class 12]]

Tyndall effect: scattering of light by colloidal particles, making beam visible. True solutions don't scatter; suspensions settle. Used to distinguish colloids. [[NCERT Chemistry Class 12]]

Incomplete dominance: heterozygote shows intermediate phenotype (e.g., red × white snapdragon → pink). Differs from codominance (both alleles expressed, e.g., AB blood group). [[NCERT Biology Class 12]]

ΔG = ΔH - TΔS. If ΔG < 0, process is spontaneous; ΔG > 0, non-spontaneous; ΔG = 0, equilibrium. Unifies enthalpy and entropy for predicting reaction feasibility. [[NCERT Chemistry Class 11]]

Work function (φ) is the threshold energy for photoelectric emission. Einstein's equation: K_max = hν - φ. Central to quantum explanation of photoelectric effect. [[NCERT Physics Class 12]]

Hydrogen bonding occurs when H is bonded to highly electronegative N, O, or F. NH₃ forms intermolecular H-bonds, explaining its high boiling point vs. PH₃. Critical for molecular properties. [[NCERT Chemistry Class 11]]

This chaining via hashes ensures immutability: altering one block changes its hash, breaking the chain. Combined with consensus mechanisms, it provides security and transparency. [[NITI Aayog Reports]]

de Broglie hypothesis: λ = h/p, where p = momentum. Establishes wave-particle duality for matter. Verified by electron diffraction experiments. Foundational quantum mechanics. [[NCERT Physics Class 12]]

Zero-order: rate = k, so k has same units as rate (concentration/time). First-order: s⁻¹; Second-order: L mol⁻¹ s⁻¹. Unit analysis helps identify reaction order. [[NCERT Chemistry Class 12]]

Interference fringes in Young's experiment confirm light's wave nature (superposition principle). Photoelectric effect shows particle nature. Together they establish wave-particle duality. [[NCERT Physics Class 12]]

Coordination number = number of ligand donor atoms bonded to central metal. Here, six NH₃ molecules coordinate to Co³⁺, giving octahedral geometry. Key concept in Werner's theory. [[NCERT Chemistry Class 12]]

Adiabatic process: Q=0, so ΔU = -W. Temperature changes due to work done. Applies to rapid compression/expansion (e.g., diesel engine, atmospheric phenomena). [[NCERT Physics Class 11]]

Equivalence point: stoichiometric completion of reaction. End point: indicator color change (ideally matches equivalence). Distinction is critical for accurate titrations. [[NCERT Chemistry Class 11]]