CoachTwo liquids are miscible when they mix in all proportions into a single liquid phase; otherwise they form two layers, the less dense on top.
Examples
Example 4.15 (Water with ethanol, water with hexane)
Ethanol is miscible with water: both are protic and polar, and ethanol hydrogen-bonds with water as well as with itself. Hexane and water are immiscible. Diiodine, a molecular solid, is barely soluble in water but dissolves readily in hexane or dichloromethane: shaken with such a solvent, aqueous iodine passes into the organic layer, the principle of liquid–liquid extraction (Chapter 29).