NEET levelSingle correct optionDifficulty 1 of 3qa130
Which solid, on warming with concentrated sulphuric acid, evolves violet vapours?
AKBr
BKI
CKCl
DKNOX3
Answer: B
Iodide is oxidised by conc. HX2SOX4 to iodine, whose vapour is violet. Bromide gives reddish-brown BrX2, chloride gives colourless HCl, and nitrate gives brown NOX2.