* Ionic Compound: Aluminum sulfide is an ionic compound, meaning it's formed by the electrostatic attraction between positively charged aluminum ions (Al³⁺) and negatively charged sulfide ions (S²⁻).

* Hydrolysis: When aluminum sulfide is added to water, it undergoes hydrolysis. This means the sulfide ions react with water molecules, forming hydrogen sulfide (H₂S), a highly toxic and foul-smelling gas.

* Precipitation: The reaction of aluminum sulfide with water also results in the formation of aluminum hydroxide (Al(OH)₃), which is an insoluble solid and precipitates out of the solution.

Therefore, the overall reaction leads to the decomposition of aluminum sulfide, the release of toxic gas, and the formation of a solid precipitate, making it effectively insoluble in water.