Question

Which compound is required to liberate bromine from aqueous solution of HBr?

Answer 1

Chlorine. This is due to the reactivity of F, Cl, Br, and I. The reactivity series of halogens is :

F > Cl > Br > I. So the more reactive chlorine will replace the less reactive bromine to give 2HCl and Br2. You can also use fluorine.