Which of the following statements `is//are` correct?

Options

A. Methane was named as fire damp as it forms explosive mixture with air.
B. Primary suffixes are added to root word to show saturation or unsaturation in a `C` atom.
C. The `IUPAC` name of valeric acid is pentanoic acid.
D. The common name of hexanoic acid is caproic acid.

Explanation

To determine which of the statements provided in the question are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Methane was named as fire damp as it forms explosive mixture with air.**
- **Analysis:** Methane (CH₄) is indeed known as "fire damp" because it can form explosive mixtures with air (oxygen). This is true as methane is flammable and can lead to explosions in confined spaces when mixed with air.
- **Conclusion:** This statement is **correct**.

2. **Statement 2: Primary suffixes are added to root words to show saturation or unsaturation in a carbon atom.**
- **Analysis:** In organic chemistry, primary suffixes like -ane, -ene, and -yne indicate the saturation level of hydrocarbons. For example, -ane indicates a saturated hydrocarbon (single bonds), while -ene and -yne indicate unsaturated hydrocarbons (double and triple bonds, respectively).
- **Conclusion:** This statement is **correct**.

3. **Statement 3: The IUPAC name of valeric acid is pentanoic acid.**
- **Analysis:** Valeric acid is indeed the common name for pentanoic acid, which has five carbon atoms and a carboxylic acid functional group (COOH). The IUPAC naming system confirms this.
- **Conclusion:** This statement is **correct**.

4. **Statement 4: The common name of hexanoic acid is caproic acid.**
- **Analysis:** Hexanoic acid, which has six carbon atoms, is commonly known as caproic acid. This is a well-established name in organic chemistry.
- **Conclusion:** This statement is **correct**.

### Final Conclusion:
All four statements are correct.