When an enantiomerically pure acid reacts with a racemic mixture of an alcohol, the reaction is a nucleophilic substitution. The acid (electrophile) is chiral and pure, but the alcohol (nucleophile) is racemic, meaning it has equal amounts of both enantiomers. Each enantiomer of the alcohol will react at the same rate with the pure acid, producing two different diastereomeric esters. Since these products are diastereomers, they have different physical properties and are formed in equal amounts, resulting in a racemic mixture.

The reaction is: Pure R-COOH + (R'-OH and S'-OH) → R-COO-R' and R-COO-S'.

Final answer: Racemic mixture