2, 4-dichlorophenoxy acetic acid is the important weed killer known as 2,4 - D. Outline its synthesis.

Explanation

### Step-by-Step Solution for the Synthesis of 2,4-Dichlorophenoxyacetic Acid (2,4-D)

1. **Starting Material**: Begin with phenol (C6H5OH), which is commercially available.

2. **Chlorination of Phenol**:
- React phenol with chlorine (Cl2) in the presence of iron (Fe) as a catalyst.
- This reaction involves electrophilic aromatic substitution, where chlorine acts as an electrophile.
- The chlorine atoms will substitute at the 2 and 4 positions of the phenol ring, resulting in the formation of 2,4-dichlorophenol (C6H3Cl2OH).
...