Thionyl chloride is preferred because it forms alkyl halides along with escapable gases SO₂ and HCl, ensuring the production of pure alkyl halides. The gaseous products can be easily removed.

In the common system, dihalogen derivatives use prefixes o-, m-, p-, while in the IUPAC system, numerals 1,2; 1,3; and 1,4 are used to denote the positions of halogen atoms in the benzene ring.

The configuration is inverted during the SN₂ reaction as the attacking nucleophile attaches to the carbon, resembling an umbrella turning inside out in a strong wind. This inversion of configuration occurs in the transition state as the reaction progresses.

In the SN₂ reaction, the incoming nucleophile interacts with the alkyl halide, causing simultaneous breaking of the carbon-halide bond and formation of a new bond between carbon and the attacking nucleophile. The transition state involves the inversion of configuration as ...

The reaction between CH₃Cl and hydroxide ion follows second-order kinetics, indicating a bimolecular nucleophilic substitution (SN₂) reaction where the rate depends on the concentrations of both reactants.