Miscibility

Diesel fuel is immiscible in water. The bright rainbow pattern is the result of thin-film interference.

Miscibility (/ˌmɪsɪˈbɪlɪti/) is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration), forming a homogeneous mixture (a solution). Such substances are said to be miscible (etymologically equivalent to the common term "mixable"). The term is most often applied to liquids but also applies to solids and gases. An example in liquids is the miscibility of water and ethanol as they mix in all proportions.^[1]

By contrast, substances are said to be immiscible if the mixture does not form a solution for certain proportions. For one example, oil is not soluble in water, so these two solvents are immiscible. As another example, butanone (methyl ethyl ketone) is significantly soluble in water, but these two solvents are also immiscible because in some proportions the mixture will separate into two phases.^[2]

^ Wade, Leroy G. (2003). Organic Chemistry. Pearson Education. p. 412. ISBN 0-13-033832-X.
^ Stephen, H.; Stephen, T. (2013-10-22). Binary Systems: Solubilities of Inorganic and Organic Compounds, Volume 1P1. Elsevier. ISBN 9781483147123.

[wade-2003-1] Wade, Leroy G. (2003). Organic Chemistry. Pearson Education. p. 412. ISBN 0-13-033832-X.

[2] Stephen, H.; Stephen, T. (2013-10-22). Binary Systems: Solubilities of Inorganic and Organic Compounds, Volume 1P1. Elsevier. ISBN 9781483147123.

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