How do halogens react with water?

Halogens react with water to form halogenated water and halogen acids, but the reactivity varies among different halogens.

Halogens are a group of elements in the periodic table consisting of fluorine, chlorine, bromine, iodine, and astatine. They are known for their high reactivity, especially with water. When halogens react with water, they form halogenated water and halogen acids. However, the reactivity of halogens with water varies among the different halogens.

Fluorine is the most reactive of the halogens and reacts explosively with water to form hydrogen fluoride (HF) and oxygen. Chlorine, on the other hand, reacts slowly with water to form hydrochloric acid (HCl) and hypochlorous acid (HClO). This reaction is facilitated by sunlight.

Bromine and iodine are less reactive and only partially react with water. Bromine water is a mixture of bromine and water, and it can be formed by simply dissolving bromine in water. Iodine reacts with water to form iodic acid (HIO3), but the reaction is very slow and requires a catalyst.

Astatine, the heaviest halogen, is radioactive and not much is known about its reactions with water. However, it is believed to react similarly to iodine.

In summary, the reactivity of halogens with water decreases down the group, from fluorine to astatine. This is due to the increase in atomic size and decrease in electronegativity, which reduces the ability of the halogen to attract the electrons from the water molecules. Understanding these reactions is crucial in chemistry as it helps predict the behaviour of these elements in different conditions.