Which one of the following is not an organochlorine?

Options

A. Parathion
B. DDT
C. BHC
D. Aldrin

Answer

To determine which of the given options is not an organochlorine, we need to understand what organochlorines are. Organochlorines are compounds that contain carbon and chlorine, typically characterized by the presence of at least one covalent bond between carbon and chlorine atoms.

Now, let's analyze the options one by one:

1. **Parathion**: This is an organophosphate pesticide, which means it does not primarily consist of carbon-chlorine bonds. Therefore, it is not classified as an organochlorine.

2. **BHC (Benzene Hexachloride)**: This is indeed an organochlorine compound, as it contains multiple chlorine atoms bonded to a carbon structure.

3. **DDT (Dichloro-Diphenyl-Trichloroethane)**: This is a well-known organochlorine pesticide, containing chlorine atoms bonded to a carbon structure.

4. **Eldrin**: This is also an organochlorine compound, used as a pesticide and contains chlorine in its structure.

From this analysis, we can conclude that **Parathion** is not an organochlorine.

### Final Answer:
**Parathion is not an organochlorine.**