Miscibility refers to the ability of a gas or liquid to dissolve uniformly in another gas or liquid.Gases mix with each other in all proportions, but this may or may not apply to liquids, where miscibility depends on chemical affinity. Ethanol, an alcohol, and water are miscible because they are chemically similar, but benzene and water are only slightly miscible because of the very large differences in their chemical properties.

Some liquids are essentially insoluble in other liquids, e.g., gasoline in water (and water in gasoline);such liquids are said to be immiscible. Other liquids are only soluble up to a point. In the case of water and ethyl ether (CH₃CH₂OCH₂CH ₃), it is possible to dissolve up to about 4 g of ethyl ether in 100 g of water, but the addition of more ethyl ether results in the production of separate layers of the...