What is a heterogeneous mixture? Give one example.

Hint: When two or more substances are mixed together in any proportion, it is said to be a mixture. Salt in water, iron in sand are two random examples of a mixture. A mixture can be either heterogeneous or homogeneous.

Complete step by step answer:
- A heterogeneous mixture is a mixture in which two or more substances are mixed together in any proportion, but the composition of the substances is not uniform throughout the mixture. A heterogeneous mixture has two or more than two distinct phases. The components of a heterogeneous mixture can be spotted visually and distinguished, either by the naked eye or can be seen under a microscope.
- Let’s consider for instance a mixture of Sulphur powder and iron filings. We can easily see the distinct constituents of the mixture with the naked eye lying along with each other. Also, if we consider milk, which is a heterogeneous mixture despite the fact that it looks like a homogenous one. It is a mixture of oil in water. Under a microscope, we can clearly see the components of milk distinctly, that is, oil droplets suspended in a clear liquid.
- Some other examples of a heterogeneous mixture are smoke, which is a mixture of carbon particles in air, oil in water, copper turnings in sand etc.

Note:
The other type of mixture apart from heterogeneous is a homogeneous mixture. Unlike the former, a homogeneous mixture has a uniform composition of the substance throughout. Its components cannot be seen by the naked eye or by the use of a microscope. A solution of salt in water is a homogeneous mixture.