Final answer:
Acetic acid/acetate ion is not typically a positively charged ion used in iontophoresis. It would more commonly carry a negative charge and move towards the positive electrode, reflecting its acidic nature and the iontophoresis principle that ions migrate towards electrodes of opposite charge.
Step-by-step explanation:
The commonly used iontophoresis drug that has a positive polarity is the acetic acid/acetate ion. Under certain conditions, acetic acid can release a proton and become acetate ion, which is negatively charged. However, when considering the characteristics of iontophoresis drugs, it is essential to look at the overall charge of the molecules in solution. In iontophoresis, the positively charged drugs are usually basic and move towards the negative electrode.
Analysis of the iontophoretic solution and ion-dipole interactions suggests that acetic acid likely forms a neutral species or an acidic species in solution, neither of which would be expected to carry a positive charge. Rather, the molecule or ion would have a net negative charge in most circumstances. Therefore, if a substance is required to have a positive polarity for iontophoresis, acetic acid would not typically fit the description unless specified under particular conditions that might cause it to be positively charged.
We can infer from the given information that iontophoresis utilizes electricity to move charged substances across a membrane, and ions respond to electric fields based on their charge, migrating towards electrodes of the opposite charge. Based on the concept that acidic substances typically carry a negative charge due to the donation of protons, it is less likely that acetic acid would possess a positive polarity.