Bromine can be released from a potassium bromide (KBr) solution by using which substance?

Bromine can be displaced from a potassium bromide (KBr) solution by a more reactive halogen. In halogen displacement reactions, a more reactive halogen replaces a less reactive halide ion from its compound. The reactivity of halogens decreases down the group: fluorine > chlorine > bromine > iodine.

Since chlorine (Cl₂) is more reactive than bromine, it can oxidize bromide ions (Br⁻) to bromine (Br₂). The reaction can be written as:

Cl2+2KBr→Br2+2KClCl_2 + 2KBr → Br_2 + 2KClCl2+2KBr→Br2+2KCl

Iodine (I₂) is less reactive than bromine, so it cannot displace bromine from KBr. Sodium chloride (NaCl) and potassium iodide (KI) are also not strong enough to liberate bromine.

This type of reaction is called a halogen displacement reaction, a subset of redox reactions, where the more reactive halogen is reduced while the halide ion is oxidized. Understanding this concept helps students predict the outcomes of reactions involving halogens and their salts.

Halogen displacement reactions are important in laboratories and industry. For example, chlorine is used to extract bromine from seawater and brine solutions in chemical industries. These reactions also illustrate the reactivity trend of halogens and the concept of oxidizing agents.

This question emphasizes practical inorganic chemistry concepts and reinforces the hierarchy of halogen reactivity, helping students understand why chlorine can liberate bromine from its compounds while other halogens cannot.