The conversion of a carboxylic acid to its corresponding acid chloride using thionyl chloride SOCl2 is a common reaction in organic chemistry. The balanced chemical equation for this reaction is:RCOOH + SOCl2 RCOCl + SO2 + HClHere, R represents an alkyl or aryl group.The mechanism for this reaction can be described in the following steps:1. Nucleophilic attack by the carboxylic acid oxygen on the sulfur atom of thionyl chloride: The lone pair of electrons on the oxygen atom of the carboxylic acid attacks the electrophilic sulfur atom of thionyl chloride, forming a tetrahedral intermediate. This step also results in the cleavage of one of the S-Cl bonds, releasing a chloride ion Cl- .2. Proton transfer: The negatively charged chloride ion abstracts a proton H+ from the tetrahedral intermediate, leading to the formation of a hydroxyl group -OH and a negatively charged oxygen atom on the sulfur.3. Leaving group departure: The negatively charged oxygen atom on the sulfur forms a double bond with the sulfur atom, causing the release of sulfur dioxide SO2 gas. Simultaneously, the hydroxyl group -OH acts as a leaving group, resulting in the formation of the acid chloride RCOCl and a water molecule H2O .4. Final proton transfer: The water molecule abstracts a proton H+ from the hydrochloric acid HCl that was formed in the first step, leading to the formation of a hydronium ion H3O+ and a chloride ion Cl- .Overall, the reaction involves the nucleophilic attack of the carboxylic acid oxygen on thionyl chloride, followed by a series of proton transfers and leaving group departures, resulting in the formation of the corresponding acid chloride, sulfur dioxide, and hydrochloric acid.