Naphthalene is not soluble in water. It is a polycyclic aromatic hydrocarbon that has a chemical structure which makes it largely hydrophobic. When placed in water, naphthalene molecules tend to aggregate together rather than dispersing uniformly.
The reason for this insolubility lies in the intermolecular forces at play. Water, which is a polar solvent, effectively dissolves other polar substances due to hydrogen bonding. Naphthalene, however, is nonpolar and does not interact favorably with water molecules. Instead, it prefers to interact with other nonpolar substances.
This property is significant in various applications, such as in the production of mothballs, where naphthalene’s ability to sublimate (transition from a solid to a gas) without dissolving in moisture is beneficial. In practical terms, if you’re looking to dissolve naphthalene, you might consider using organic solvents such as ethanol or acetone, which can effectively solubilize it.