Halogen Reactivity and Oxidizing Properties

Steps:

• Evaluate option A: Iodine's solid state results from strong intermolecular forces due to large size, not I-I bond strength.
• Evaluate option B: HI decomposes more readily than HCl due to weaker H-I bond, but statement is incomplete and unclear.
• Evaluate option C: Chlorine displaces iodine from KI, producing purple I2 vapor, but explanation misstates "iodide" instead of "iodine."
• Identify option D: Concentrated H2SO4 oxidizes I- to I2, confirmed by purple vapor observation.

Why D is correct:

• Concentrated H2SO4 acts as an oxidizing agent (via SO4^2- reduction to SO2), oxidizing I- to I2 per the reaction: 2I- + H2SO4 → I2 + SO2 + H2O.

Why the others are wrong:

• A: I-I bond is weak (bond energy 151 kJ/mol), not high; solid state due to van der Waals forces.
• B: Statement garbled; lacks clear comparison of HI vs. HCl decomposition.
• C: Chlorine stronger oxidizing agent than iodine (E° Cl2 = 1.36 V > I2 = 0.54 V), not "iodide" (a reducing agent).

Final answer: D