Trends in hydrogen halide properties down the group Steps: - Identify ease of oxidation: Halide ions (X⁻) become easier to oxidize down the group (F⁻ to I⁻) as standard reduction potentials for X₂/X⁻ decrease, making oxidation more favorable. - Recall bond dissociation energy: H–X bond strength decreases down the group (HF strongest, HI weakest) due to increasing atomic size of X. - Match to table: The row showing "easier to oxidise down the group" for oxidation and "decreases down the group" for bond energy (or similar property like thermal stability) is correct. - Confirm choice: Option C aligns with both trends. Why C is correct: - Halide oxidation follows the electrochemical series law, where E° decreases from F₂ (2.87 V) to I₂ (0.54 V), easing X⁻ → ½X₂ + e⁻ down the group; bond energy decreases per Fajans' rules on size mismatch. Why the others are wrong: - A: Second part wrong; bond energy decreases, not increases. - B: First part wrong; oxidation eases, not becomes more difficult. - D: Both parts wrong; oxidation eases and property decreases. Final answer: …