Select the wrong statement
I. Compounds are made up of two or more elements in definite proportion. II. Mixtures contain elements in any proportions. III. Milk is a homogenous mixture. IV. Air is a homogenous mixture.
Which of the statement(s) given above is/are incorrect?

Options

A. I and III
B. I and II
C. only III
D. III and IV

Explanation

To solve the question of selecting the wrong statement among the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze Statement I:**
- Statement I states that "Compounds are made up of two or more elements in definite proportion."
- This statement is **true**. Compounds have a fixed ratio of elements. For example, in water (H₂O), there are always two hydrogen atoms for every one oxygen atom.

**Hint:** Remember that compounds have a specific formula that defines the ratio of their constituent elements.

2. **Analyze Statement II:**
- Statement II states that "Mixtures contain elements in any proportions."
- This statement is also **true**. Mixtures can have varying amounts of their components. For instance, in a mixture of salt and water, you can have different amounts of salt dissolved in the water.

**Hint:** Mixtures can be adjusted in composition, unlike compounds which have fixed ratios.

3. **Analyze Statement III:**
- Statement III states that "Milk is a homogeneous mixture."
- This statement is **false**. Milk is actually a **heterogeneous mixture** because it contains fat globules dispersed in water, which do not form a uniform composition throughout.

**Hint:** A homogeneous mixture appears uniform throughout, while a heterogeneous mixture has distinct, separate components.

4. **Analyze Statement IV:**
- Statement IV states that "Air is a homogeneous mixture."
- This statement is **true**. Air is considered a homogeneous mixture because it contains various gases (like nitrogen, oxygen, carbon dioxide) that are uniformly mixed.

**Hint:** Homogeneous mixtures have a consistent composition, which is true for gases in the air.

### Conclusion:
After analyzing all the statements, we find that the only incorrect statement is Statement III. Therefore, the answer to the question is:

**The wrong statement is: Statement III.**

### Summary of Incorrect Statements:
- **Only Statement III is incorrect.**