Which term describes a liquid that can combine with water without separating?

The term that describes a liquid that can combine with water without separating is "miscible." When two liquids are miscible, they can mix in any proportion to form a homogeneous solution. This characteristic is commonly observed in liquids that can interact favorably at the molecular level, allowing them to dissolve completely in one another.

For example, ethanol is miscible with water; when mixed, they form a single uniform liquid. The ability of a liquid to be miscible with water is essential in various applications, such as in creating solutions for chemical reactions, cleaning agents, or integrating substances in different industries.

In contrast, the term "immiscible" describes liquids that do not mix and will separate when combined, like oil and water. "Nonpolar" refers to molecules that do not carry a significant charge and often do not interact well with polar solvents like water, leading to miscibility issues. "Supercritical" refers to a state of matter beyond the critical point where distinct liquid and gas phases do not exist, which does not apply to the miscibility of liquids in conventional solutions. Thus, "miscible" is the accurate term for liquids that combine with water seamlessly.