Question

When a liquid will not mix in any proportions with another liquid what is it termed?

Answer 1

The term is `"immiscible"`.

Explanation:

Immiscible liquids, e.g. water and ether, hexanes and methanol, are more or less insoluble in each other, and often used to partition and separate a solute across a liquid/liquid boundary.

Solvents that dissolve in each other are termed `"miscible"`. Examples of miscible liquids include, `"water/methanol; hexanes/ethanol;"`
`"diethyl ether/hexanes"`.