Sodium sulfide, represented by the chemical formula Na2S, is an inorganic compound composed of sodium and sulfur. It typically appears as a yellow to red solid and is highly soluble in water, forming a strongly alkaline solution. Sodium sulfide is often used in various industrial applications, including paper manufacturing, water treatment, and as a reducing agent in chemical processes. In its solid form, Na2S can release hydrogen sulfide gas when it reacts with acids, which has a characteristic rotten egg smell. Due to its reactivity, sodium sulfide must be handled with care, as it can be hazardous to health and the environment.