MODEL RELEASED. Displacement reaction. Student pouring chlorine water into a test tube containing potassium bromide solution (KBr). The KBr solution was colourless. Bromine (Br2, yellow/orange) has formed as it is displaced from solution by the more reactive chlorine (Cl2). This results in a mixture of bromine water and potassium chloride (KCl) solution. This experiment shows that chlorine should be ranked above bromine in a reactivity series. The reaction equation is: Cl2 + 2 KBr ----> 2 KCl + Br2