Which of the following is not a mixture?

Options

A. air
B. sea water
C. ice
D. soil

Explanation

To determine which of the following options is not a mixture, we first need to understand the definition of a mixture. A mixture is a combination of two or more substances that are not chemically bonded and can be separated by physical means.

Let's analyze the options provided:

1. **Air**: Air is a mixture of different gases, primarily nitrogen and oxygen, along with other gases. Since these gases are mixed physically and can be separated, air is a mixture.

2. **Sea Water**: Sea water is a mixture of water and various dissolved salts, including sodium chloride (NaCl). The components can be separated by physical means (like evaporation), so sea water is also a mixture.

3. **Ice**: Ice is the solid form of water, which is chemically composed of H2O. It is formed by a chemical reaction between hydrogen and oxygen gases. Since ice is a pure substance with a definite chemical composition, it is not a mixture.

4. **Soil**: Soil consists of various components such as minerals, organic matter, air, and water. These components are mixed physically and can vary in composition, making soil a mixture.

Based on this analysis, the substance that is not a mixture is **Ice**.

**Final Answer**: Ice is not a mixture.

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