Benzene reacts with phosgene to form Benzoyl chloride.

Explanation:
1. Reaction:
The reaction between benzene and phosgene involves the substitution of a hydrogen atom in benzene with a chlorine atom from phosgene. This reaction is known as the Friedel-Crafts acylation reaction.

2. Friedel-Crafts Acylation Reaction:
The Friedel-Crafts acylation reaction involves the addition of an acyl group (RCO-) to an aromatic ring. In this case, benzene (C6H6) acts as the aromatic ring, and phosgene (COCl2) acts as the acylating agent.

3. Mechanism:
The reaction proceeds through the following steps:
- The reaction begins with the formation of an acylium ion (RCO+), which is generated by the reaction of phosgene with a Lewis acid catalyst, typically aluminum chloride (AlCl3).
- The Lewis acid catalyst, AlCl3, accepts a chlorine atom from phosgene, resulting in the formation of AlCl4- and COCl+.
- The COCl+ ion then reacts with benzene, where one of the hydrogen atoms in benzene is substituted by the COCl+ ion, resulting in the formation of benzoyl chloride (C6H5COCl) and HCl.
- The Lewis acid catalyst, AlCl3, is regenerated at the end of the reaction and can participate in further reactions.

4. Benzoyl Chloride:
Benzoyl chloride (C6H5COCl) is an important organic compound used in various chemical reactions. It is a colorless liquid with a strong odor. Benzoyl chloride is a versatile reagent and is commonly used in the synthesis of pharmaceuticals, dyes, and perfumes. It can react with various nucleophiles to form a wide range of derivatives.

In conclusion, when benzene reacts with phosgene, the Friedel-Crafts acylation reaction takes place, resulting in the formation of benzoyl chloride (C6H5COCl).