Glossary / Physical properties
Solubility in water
Solubility in water is the extent to which a substance dissolves in water, usually reported at a stated temperature. It determines whether a chemical mixes with water or stays separate, which affects spill cleanup, fire-fighting choices and how the chemical moves in the environment.
Explanation
Substances range from completely miscible, meaning they mix in all proportions, to practically insoluble. SDSs may describe this in words or as a quantity per volume of water, and the value changes with temperature. The solubility of other solvents is also sometimes given.
For spills, the answer shapes the response. A water-soluble liquid can be diluted and may flow into drains and sewers quickly, so containment must happen early. A material that does not dissolve may float or sink, which links to Specific gravity. Water-based extinguishing agents may spread a floating flammable liquid, while water-soluble flammable liquids such as alcohols may need special foam designed to resist being broken down.
Solubility also matters for health and the environment. Water-soluble chemicals can be absorbed through moist tissues like the eyes and lungs, and may be carried easily into groundwater. Very poorly soluble but fat-soluble chemicals may build up in organisms; see Bioaccumulation and LogKow (octanol-water partition coefficient) for that behavior.
Reactive materials are a special case. For some chemicals, contact with water is not a dissolving event but a dangerous reaction, so never assume water is a safe cleanup medium. Check Water-reactive and Section 10 of the SDS before using it.
What to do and watch for
- Use solubility to decide how to contain a spill and whether drains must be protected.
- Do not use water on a spill until the SDS confirms it is safe.
- Remember that dissolving in water does not make a chemical harmless.
Where it appears on an SDS
- Section 9: Physical and chemical properties. Reports solubility in water and sometimes in other solvents, often with the temperature of measurement.
- Section 12: Ecological information. Mobility in soil and water is discussed using solubility and related partitioning data.
SDS content and wording vary by supplier. This page is general reference and does not replace the current SDS for your product.