Concentrated $H_2SO_4$ is not used to prepare $HBr$ from $KBr$ because it

Aluminium trifluoride is insoluble in anhydrous $HF$ but dissolves on addition of $NaF$. Aluminium trifluoride precipitates out of the resulting solution when gaseous $BF_3$ is bubbled through. Give reasons.

$KI$ when heated with conc. $H_2SO_4$ gives:

Give the reason for the bleaching action of $Cl_{2}$.

Mark the element which displaces three halogens from their compounds.

Which of the following statements is correct regarding halogens?