What is miscibility?

• A. The ability to be melted into a liquid.
• B. The ability to dissolve in water.
• C. The ability to be mixed or blended with another substance.
• D. The tendency to separate from a mixture.

Answer: (C)

Miscibility is the ability of two liquids to mix together in all proportions to form a single, uniform phase. When liquids are miscible, they blend completely rather than separating into layers. This matters in HazMat work because a solvent that is miscible with water will dissolve in water and can spread contamination more broadly, while an immiscible liquid will form a distinct layer and behave differently in containment and cleanup. The other ideas refer to different properties: melting is a solid turning into a liquid, solubility in water is about dissolving in water rather than mixing with another liquid, and a tendency to separate describes immiscibility. So the best description is the ability to be mixed or blended with another substance.