Question

\[{{F}_{2}}\] is a stronger oxidising agent than \[C{{l}_{2}}\]. Explain.

Answer 1

Hint: The halogens such as bromine, chlorine, fluorine and iodine are considered to be having strong oxidising power because they have high electronegativity value. They have the tendency to gain the electron as they need only one electron to get the nearest noble gas configuration. This tendency of the element to gain electrons is called reduction. This means halogens get easily reduced.

Complete step-by-step answer:
The substance which reduces itself is called an oxidising agent. When a halogen atom is present, the atom of the other element instantly loses its electron to complete the halogen octet. The property of losing the electrons is called oxidation. This means in the presence of halogens the other atom gets oxidised. The factors which affect the oxidising tendency are bond dissociation enthalpy, hydration enthalpy and electron gain enthalpy. As the electronegativity increases the oxidising power of halogen increases.

Fluorine is the most electronegative element in the periodic table. The electron gain enthalpy increases with the increase in atomic size. We know fluorine has a small size so it will have low electron gain enthalpy as comparison chlorine because the size of chlorine is more than fluorine. But on contrast fluorine has low bond dissociation energy and high hydration energy than in comparison to chlorine.

This high value of fluorine by low bond dissociation energy and hydration energy compensates its low electron gain enthalpy. Despite having low electron gain enthalpy it is the stronger oxidising agent than chlorine because of the high hydration energy and low bond dissociation energy.

Note: Fluorine has the tendency to oxidise all other halogens in its solid phase. While chlorine can oxidise bromine and iodine only. Bromine can oxidise only iodide ion. The electronegativity value of fluorine is 3.98 according to Pauling scale.