(a) Those mixtures in which the substances are completely mixed together and are indistinguishable from one another, are called homogeneous mixtures. A homogeneous mixture has a uniform compositon throughout its mass. It has no visible boundaries of separation between the various constituents. A mixture of sugar in water (called sugar solution) is a homogeneous mixture because all the parts of sugar solution have the same sugar-water composition and appear to be equally sweet. There is no visible boundary of separation between sugar and water particles in a sugar solution. A mixture of two (or more) miscible liquides is also a homogeneous mixture. For example, a mixture of alcohol and water is a homogeneous mixture. All the homogeneous mixtures are called solutions.
(b) Those mixtures in which the substances remain separted and one substance is spread throughout the other substance as small particles, froplets or bubbles, are called hetrogeneous mixture does not have a uniform composition throughout its mass. It has visible boundaries of separation between the various constituents. The mixture of sugar and sand is a hetrogeneous mixture because different parts of this mixture will have different sugar-ands composition. Some parts of this mixture will have more of sugar particles whereas other parts will have more of sand particles. There is a visible boundary of separation between sugar and sand particles. The suspension of solids in liquids are also heterogeneous miztures. For example, a supernion of chalk in water is a heterogeneous mixture. A mixture containing two (or more) immiscible liquids is also a heterogeneous mixture. For example, a mixture of petrol and water is a heterogeneous mixturre.
