Question

Write the reaction of $${\text{F}}_2$$ with water.

Answer 1

Hint: In water, hydrogen atom is electropositive and oxygen atom is electronegative. Fluorine is also electronegative. The electropositive hydrogen from water will combine with electronegative fluorine.

Complete answer:
The chemical properties of fluorine are slightly different from other halogens. This is known as anomalous behavior of fluorine. Fluorine shows anomalous behavior due to small size, large electronegativity, low bond dissociation enthalpy and absence of d orbitals. Among halogens, fluorine shows maximum reactivity. The only oxidation state of fluorine is -1. Hydrogen fluoride, a compound of fluorine shows intermolecular hydrogen bonding
Fluorine vigorously reacts with water to form hydrogen fluoride and oxygen. Sometimes, instead of oxygen, ozone is produced.
$$\text{2}{\text{F}}_{\text{2}}\text{ + 2}{\text{H}}_{\text{2}}\text{O}\to \text{4HF + }{\text{O}}_{\text{2}}$$
$$\text{3}{\text{F}}_{\text{2}}\text{ + 3}{\text{H}}_{\text{2}}\text{O}\to \text{6HF + }{\text{O}}_{\text{3}}$$
In the above reactions, fluorine is reduced to fluoride ion. Oxide ions are oxidized to either oxygen molecules or ozone molecules. Hydrogen fluoride is a weak acid. However, when chlorine reacts with water, hydrogen chloride and oxygen are obtained. Ozone is not formed.
$$\text{2C}{\text{l}}_{\text{2}}\text{ + 2}{\text{H}}_{\text{2}}\text{O}\to \text{4HCl + }{\text{O}}_{\text{2}}$$
Fluorine is highest electronegativity and low dissociation energy. The low bond dissociation energy of fluorine means low activation energy for the reaction of fluorine. Hence, fluorine is highly reactive. It reacts almost instantaneously with any element. Also, fluorine is a very strong oxidizing agent. Fluorine itself gets reduced in the redox reaction.

Note: Oxygen and ozone are allotropes. Oxygen molecules contain two oxygen atoms. Ozone molecules contain three oxygen atoms.