Water mixed with alcohol and water mixed with mint syrup are a couple examples of miscible liquids. A liquid is considered miscible if it can mix with another miscible liquid to form a homogeneous mixture.
A homogeneous mixture is a uniform solution or a solution with the same structure throughout the mixture. If two liquids do not form a homogeneous solution when mixed together, the liquids are said to be immiscible. The mixture of water and oil is a common example of immiscibility. When water and oil are mixed together and left alone to settle, the two liquids eventually separate into two layers. A separating funnel could also be used to divide the substances into individual liquids more quickly. Water flows in more quickly, leaving the oil behind.
When testing whether two liquids are miscible or immiscible, the appearance of the resulting solution must be determined optically. If the solution contains two miscible liquids, the mixture appears as a clear liquid. If the solution contains one or more immiscible liquids, the mixture appears as a cloudy and foggy liquid. In some cases, the results of this optic test may be incorrect. If the two substances have similar indices of refraction, an immiscible mixture may appear clear.