Final answer:
KMnO4 forms solvated ions when added to water, allowing it to dissolve in water.
Step-by-step explanation:
The ability or inability of KMnO4 to dissolve in water is due to the fact that it forms solvated ions when it comes into contact with water. When solid KMnO4 is added to water, ion-dipole forces attract the positive end of water molecules to the negative ions in KMnO4, while the negative end of water molecules is attracted to the positive potassium ions. Water molecules surround the individual ions, reducing the interionic forces and allowing them to move off into solution as solvated ions. This increased disorder is responsible for the dissolution of KMnO4 in water.