As we look around, we can see that most of the matter around us exist as mixtures of two or more pure components, for example, sea water, minerals, soil etc. are all mixtures. A mixture consists of two or more different substances mixed together in any proportions.
On the basis of the uniformity of the constituents, the mixture can be classified as homogeneous mixtures and heterogeneous mixtures. Homogeneous mixture is a mixture in which the constituents are uniformly distributed throughout its volume and cannot be seen separately. For example, salt solution, sugar solution, brass, vinegar, etc. Heterogeneous mixture is a mixture in which the constituents are not uniformly distributed throughout its volume and can be easily seen separately. For example, mixture of iron filings and sulphur powder, salt and sand, water and chalk powder, etc.
On the basis of physical state, mixtures can be divided into three categories, solid-solid, solid-liquid and liquid-liquid mixtures.
Solid-solid mixtures consist of two or more different solid substances mixed together. Solid-liquid mixtures can be prepared by mixing a solid substance in a liquid substance. Liquid-liquid mixtures are prepared by mixing different types of liquids.