Final answer:
To make an aqueous potassium iodate solution, potassium iodate (KIO3) should be dissolved in water, as this compound directly provides the iodate ions needed for the solution.
Step-by-step explanation:
An aqueous potassium iodate solution is made by dissolving a substance that will provide the iodate ion (IO3ā). In this context, the information provided about potassium hydroxide (KOH) and iodine (I2) are relevant. Potassium hydroxide itself is a highly soluble ionic compound that completely dissociates in water to yield hydroxide ions. Iodine can react with iodide ions in aqueous solutions, which might suggest that a compound such as potassium iodide (KI) would provide the necessary iodide ion (Iā) to form the iodate ion when reacted with an appropriate oxidizing agent. However, the direct substance to be dissolved to obtain iodate ions would be potassium iodate (KIO3) itself, not mentioned directly in the provided materials. This substance would dissociate in water to give the desired iodate ions (IO3ā) and potassium ions (K+).