Ace the IGCSE Organic Chemistry Test 2026 – Ignite Your Knowledge and Conquer the Elements!

Bromine in the bromine water test behaves as an electrophile that adds across a carbon–carbon double bond. The C=C bond is electron-rich, so it polarizes Br2 and causes each bromine atom to attach to a different carbon, converting the alkene into a dibromoalkane. As this addition happens, the bromine is consumed and the orange-brown color of bromine water fades, giving a decolorized solution. This is why bromine’s role is described as adding across the double bond, not acting as a solvent or a catalyst, and not causing cleavage into fragments.