Question 1
Multiple choiceMedium1 markIn a simulation, bromine water is added separately to aqueous potassium chloride and potassium iodide. Which prediction follows from the Group 17 trend in non-metallic character?
Show answer and explanation
Answer: A. Non-metallic character and halogen reactivity decrease down Group 17. Thus, Cl₂ is more reactive than Br₂, while Br₂ is more reactive than I₂. Bromine cannot displace Cl⁻ but can displace I⁻, forming Br⁻ and I₂.
B: Reversing the reactivity order makes Br₂ appear able to displace Cl⁻ but not I⁻. C: Correctly predicts iodide displacement but wrongly extends it to chloride, whose halogen is more reactive. D: Fails to apply the reactivity comparison to iodide; Br₂ displaces I⁻. Remember: A halogen displaces the halide of a less reactive halogen.