Question

Write the reactions of $F_{2} $ and $Cl_{2}$ with water.

Answer 1

Hint: Halogens are the elements of group seventeenth of the periodic table and generally includes: Fluorine, Chlorine, Bromine and Iodine. The halogens are all oxidizing elements with fluorine and chlorine being the most electronegative elements in the group. Hence, the most oxidizing and as a result, both fluorine and chlorine are able to oxidize (react) with water to greater extents forming different products. They generally tend to form hydrogen halide (acidic) with water. Also, note that the reactions for chlorine are reversible now whereas fluorine was not.

Complete answer:
Florine spontaneously reacts with water forming hydrogen fluoride, and liberates oxygen which is highly charged with ozone. The chemical reaction can be given as follows:
$2F_{2} + 2H_{2}O \to 4F^{-}+4H^{+}+2O_{2}$
But chlorine requires exposure of sunlight to form oxygen and at room temperature. It reacts with water and forms HCl (Hydrochloric acid) and HOCl (Hypochlorous acid) and when HOCl exposes in sunlight, it gives oxygen. Due to this chlorine acts as a powerful bleaching and oxidizing agent. The reaction is shown as below:
$Cl_{2}+H_{2}O \rightleftharpoons HCl + HOCl$
$2HOCl\to2HCl + O_{2} $

Note: Halogens eagerly undergo reduction, hence act as oxidising agents. From a standard reduction potential table, it is determined that iodine and bromine cannot oxidize water to oxygen because they have smaller reduction potentials than oxygen. Thus, iodine and bromine do not react with water. However, fluorine and chlorine have larger reduction potentials, and can oxidize water. Also, note that the reactions for chlorine are reversible now whereas fluorine was not.