Which of the following is not true for mixtures?

Options

A. Mixtures can be homogeneous or heterogeneous.
B. Components in a mixture are present in a fixed ratio.
C. Properties of a mixture are the average of its components.
D. Components of a mixture can be separated easily by simple physical methods.

Explanation

To determine which statement is not true for mixtures, we need to analyze each of the provided statements about mixtures:

1. **Mixtures can be homogeneous and heterogeneous.**
- This statement is true. Mixtures can indeed be classified into two types: homogeneous (uniform composition) and heterogeneous (non-uniform composition).

2. **Components in a mixture are present in fixed ratio.**
- This statement is not true. In a mixture, the components can be present in varying ratios, meaning there is no fixed proportion of substances in a mixture. This is a key characteristic that differentiates mixtures from compounds, which have fixed ratios.

3. **The properties of the mixture are the average of its components.**
- This statement is true. The properties of a mixture generally reflect the average properties of the individual components that make it up.

4. **The components of the mixture can be separated easily by simple physical methods.**
- This statement is also true. The components of a mixture can be separated using physical methods such as filtration, evaporation, or magnetic separation.

Based on the analysis, the statement that is **not true** for mixtures is:

**"Components in a mixture are present in fixed ratio."**