Which is reducing agent? A. Gains electrons B. Loses electrons C. Accepts protons D. Gains neutrons Explanation: Reducing agent donates electrons.
Which reaction is first order? A. Rate independent of concentration B. Rate proportional to concentration C. Rate proportional to square of concentration D. Rate constant zero Explanation: First order depends linearly on reactant concentration.
Which molecule exhibits dipole moment? A. CO₂ B. BF₃ C. NH₃ D. CH₄ Explanation: NH₃ is polar due to lone pair.
Which orbital has highest energy in hydrogen atom? A. 2s B. 2p C. 3s D. All same for given n Explanation: Energy depends only on n in hydrogen.
Which compound has highest boiling point? A. CH₄ B. NH₃ C. H₂O D. HF Explanation: Water has extensive hydrogen bonding.
Which type of bonding involves delocalized electrons? A. Ionic B. Covalent C. Metallic D. Hydrogen Explanation: Metallic bonding features free electrons.
The entropy at absolute zero for perfect crystal is: A. Maximum B. Infinite C. Zero D. Undefined Explanation: Third law states entropy approaches zero.
Which constant relates energy and frequency? A. Boltzmann constant B. Planck constant C. Avogadro number D. Gas constant Explanation: (E = h\nu).
The cosmological redshift is due to: A. Doppler motion only B. Expansion of space C. Gravitational collapse D. Magnetic fields Explanation: Light stretches as universe expands.
Which particle participates in weak interaction? A. Photon B. Gluon C. W boson D. Graviton Explanation: W boson mediates weak force.