Final answer:
The concentration of both K+ ions and MnO4- ions in a 0.15 M KMnO4 solution is 0.15 M for each ion because KMnO4 dissociates completely in an aqueous solution with a one-to-one mole ratio.
Step-by-step explanation:
When a solution is made that is 0.15 M in KMnO4, it dissociates into potassium ions (K+) and permanganate ions (MnO4-). Because KMnO4 dissociates completely in aqueous solution, for every 1 mole of KMnO4 dissolved, 1 mole of K+ and 1 mole of MnO4- ions are produced.
Therefore, the concentration of K+ ions and MnO4- ions in the solution will both be 0.15 M, the same as the initial concentration of KMnO4 since the salt dissociates into one mole of each ion per mole dissolved.