Which of the following is not correctly matched with its uses?

Options

A. Methanol: As a solvent for paints, varnishes etc
B. Ethanol : For denaturing spirit, in manufacture of formaldehyde
C. Ethers : To provide inert medium for chemical reactions, as anaesthetic.
D. All are correctly matched

Answer

To solve the question regarding which of the following substances is not correctly matched with its uses, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the substances and their uses**:
- **Methanol**: Used as a solvent for paints, varnishes, etc.
- **Ethanol**: Used for denaturing spirit in the manufacture of formaldehyde.
- **Ethers**: Used to provide an inert medium for chemical reactions and as anesthetics.
- **All options**: Indicates that all substances are correctly matched.

2. **Evaluate the first option (Methanol)**:
- Methanol is indeed used as a solvent for paints and varnishes. This is a correct match.

3. **Evaluate the second option (Ethanol)**:
- Ethanol is commonly known as drinking alcohol and is used in various applications, including as a solvent and in cosmetics. However, it is **not** used in the manufacture of formaldehyde. Methanol is the compound used for this purpose. Therefore, this match is incorrect.

4. **Evaluate the third option (Ethers)**:
- Ethers, particularly diethyl ether, are used as anesthetics and can provide an inert medium for chemical reactions. This is a correct match.

5. **Evaluate the fourth option (All options)**:
- Since we found that the second option is incorrect, the statement that all options are correctly matched is also incorrect.

### Conclusion:
The option that is not correctly matched with its uses is **Ethanol for denaturing spirit in the manufacture of formaldehyde**.

### Final Answer:
**Ethanol for denaturing spirit in manufacture of formaldehyde.**

---