* Polarity: KNO3 is an ionic compound, meaning it's composed of positively charged potassium ions (K+) and negatively charged nitrate ions (NO3-). Water is a polar solvent, meaning it has a positive and negative end due to the uneven sharing of electrons. This allows water molecules to surround and interact with the ions of KNO3, dissolving it.

* Benzene and Hexane: Both benzene and hexane are nonpolar solvents. They lack the positive and negative charges needed to interact with and separate the ions in KNO3. Therefore, KNO3 will not dissolve in them.

In summary: The "like dissolves like" rule applies here. Polar compounds dissolve in polar solvents, and nonpolar compounds dissolve in nonpolar solvents.