NEET Chemistry: Chemistry - Halogens questions with solutions

Q1. Concentrated \( \boldsymbol{H}_{2} \boldsymbol{S} \boldsymbol{O}_{4} \) cannot be used to prepare HBr or HI from KBr or KI because it

1. reacts too slowly with KBr or KI
2. reduces HBr or H
3. oxidises KBror KI
4. oxidises KBr to \( K B r O_{3} \) or \( K \) I to \( K I O_{3} \)

Answer: oxidises KBr to \( K B r O_{3} \) or \( K \) I to \( K I O_{3} \)

Concentrated H2SO4 oxidizes Br− and especially I−, so the desired hydrogen halides are not obtained cleanly. Instead, bromide or iodide can be converted into bromate or iodate salts.