An acyl group is a functional group derived from a carboxylic acid by removing the hydroxyl (-OH) part. It has the general formula RCO-, where R represents a hydrocarbon chain or hydrogen. Acyl groups are important in organic chemistry as they participate in various reactions, forming compounds like esters and amides. Acyl groups can be classified into different types based on the carbon chain attached. For example, an acetyl group is a specific acyl group with the formula CH3CO-, derived from acetic acid. These groups play a crucial role in biochemical processes and the synthesis of pharmaceuticals.