The reaction is:

The reaction is:

$$\text{2KBr} + \text{Cl}_2 \longrightarrow \text{2KCl} + \text{Br}_2$$

This is a substitution reaction (also known as a single displacement reaction). In this reaction, chlorine replaces bromine in potassium bromide.

The atom which is replaced is bromine ($\text{Br}$).