Here's why:

* Fluorine is more reactive than bromine. This is due to its higher electronegativity and smaller atomic size, making it a stronger oxidizing agent.

* Fluorine displaces bromine from sodium bromide. The more reactive fluorine will react with sodium, forming sodium fluoride (NaF), while the bromine is displaced and forms elemental bromine (Br₂).

The balanced chemical equation is:

F₂ (g) + 2NaBr (aq) → 2NaF (aq) + Br₂ (l)

Key points:

* This reaction is highly exothermic, meaning it releases a lot of heat.

* The reaction is a good example of the halogen reactivity trend, where the reactivity of halogens decreases down the group (from fluorine to iodine).

* The reaction is also an example of a redox reaction, where fluorine is reduced and bromine is oxidized.