The synthesis of benzocaine from p-aminobenzoic acid and ethanol involves a Fischer esterification reaction. In this reaction, one mole of p-aminobenzoic acid reacts with one mole of ethanol to produce one mole of benzocaine and one mole of water. Therefore, the correct molar ratio of p-aminobenzoic acid to ethanol in the preparation of benzocaine is 1:1.