Explain `sp^2` hybridization with an example.

Explanation

Nucleophilic bimolecular substitution `(S_(N)^(2))` reactions: The rate of `S_(N)^(2)` reaction depends upon the concentration of both the reactants. For example, conversion of alkylhalide to aicohol by the action of alkali shows,
Rate `prop[R-X] [OH^(-)]`
The reaction between methyl chloride `(CH_(3)C)` and hydroxide ion `(OH^(-))` to yield methanol and chloride ion follows second order kinetics.
The incoming nucleophile `(- OH^(-))` interacts with the alkylhalide. The bond between the nucleophile and, the carbon atom starts forming, while the bond between carbon-atom and leaving group weakens forming.a transition state. As this, happens, the configuration of carbon atom under attack inverts in much the same way as an umbrella is turned inside out when caught in a strong wind. This process is called inversion of configuration. In the transition state the carbon atom is simultaneously bonded to incoming nucleophile and the outgoing leaving group. The carbon atom in the transition state is simultaneously bonded .to five atoms or groups and therefore is unstable and cannot be isolated.
The.order of reactivity for `S_(N)^(2)` reaction followed is. Primary Halide `gt` Secondary halide `gt` Tertiary halide.