Examples of Homolytic and Heterolytic Fission

Homolytic Fission:
Homolytic fission is a type of bond cleavage in which a covalent bond breaks, and each atom retains one of the shared electrons, resulting in the formation of two free radicals. This process occurs mainly in organic chemistry and is initiated by the input of energy, such as heat or light. Here are a few examples of homolytic fission:

1. Halogenation of Alkanes:
When an alkane, such as methane (CH4), reacts with a halogen, such as chlorine (Cl2), the covalent bond between the carbon and hydrogen atoms is broken homolytically, resulting in the formation of two methyl radicals (CH3·) and two chlorine radicals (Cl·).

CH4 + Cl2 → CH3· + HCl
CH3· + Cl2 → CH3Cl + Cl·

2. Photodissociation of Ozone:
Ozone (O3) can undergo homolytic fission when exposed to ultraviolet (UV) radiation. The bond between the oxygen atoms breaks, producing two oxygen radicals (O·) and molecular oxygen (O2).

O3 + UV radiation → O· + O2

Heterolytic Fission:
Heterolytic fission is a type of bond cleavage in which a covalent bond breaks unevenly, resulting in the formation of charged species. In this process, one atom retains both shared electrons while the other atom becomes electron deficient. Here are a couple of examples of heterolytic fission:

1. Formation of Carbocations:
In organic chemistry, when a covalent bond between a carbon atom and a hydrogen atom breaks unevenly, a carbocation (positively charged carbon atom) is formed. For instance, in the reaction between methane (CH4) and a strong acid like sulfuric acid (H2SO4), the hydrogen atom takes both shared electrons, leading to the formation of a methyl carbocation (CH3+).

CH4 + H2SO4 → CH3+ + HSO4-

2. Formation of Anions:
Similarly, heterolytic fission can result in the formation of anions (negatively charged species). One example is the reaction between sodium chloride (NaCl) and water (H2O), where the water molecule donates a lone pair of electrons to the chlorine atom, resulting in the formation of a chloride anion (Cl-).

NaCl + H2O → Na+ + Cl-

In summary, homolytic fission occurs when a covalent bond breaks evenly, producing free radicals, while heterolytic fission leads to an uneven bond cleavage, resulting in the formation of charged species like carbocations and anions. These processes play vital roles in various chemical reactions and are fundamental concepts in organic and inorganic chemistry.

cl--cl bond is homolytic where as c--cl is hetrolytic