Which factor does NOT affect equilibrium constant? A. Temperature B. Pressure C. Catalyst D. Concentration Explanation: Catalyst affects rate but not equilibrium position.
The rate law for a reaction must be determined by: A. Stoichiometry B. Experiment C. Thermodynamics D. Equilibrium constant Explanation: Reaction order is experimentally determined.
Which compound is most acidic? A. Phenol B. Ethanol C. Methane D. Ethene Explanation: Phenol stabilizes conjugate base via resonance.
Which orbital has zero probability at nucleus? A. s B. p C. d D. Both B and C Explanation: p and d orbitals have nodes at the nucleus.
Which species shows strongest hydrogen bonding? A. NH₃ B. H₂O C. HF D. CH₄ Explanation: HF has highly polar H–F bond and strong intermolecular attraction.
Which phenomenon leads to quantization of atomic energy levels? A. Classical mechanics B. Boundary conditions on wavefunctions C. Thermal motion D. Friction Explanation: Allowed solutions of Schrödinger equation are discrete due to constraints.
The electric potential inside a conductor in electrostatic equilibrium is: A. Zero B. Maximum C. Constant D. Infinite Explanation: Charges redistribute until potential is uniform inside.
The speed of light in vacuum is invariant because: A. It depends on observer motion B. It is defined constant in relativity C. It varies with energy D. It depends on medium Explanation: Special relativity postulates constant light speed in all inertial frames.
Which thermodynamic potential is minimized at constant temperature and pressure? A. Internal energy B. Helmholtz free energy C. Gibbs free energy D. Enthalpy Explanation: Gibbs free energy reaches minimum at equilibrium under constant T and P.
The entropy change for a reversible process is given by: A. (dS = \delta Q) B. (dS = \delta Q/T) C. (dS = TdQ) D. (dS = Q/T^2) Explanation: Entropy change equals heat transfer divided by temperature in reversible processes.