Step 1: Understand the reaction.
This reaction involves phenol (Ar-OH) reacting with a compound having the structure \( \text{Cl-C-R} \). When pyridine is used as a catalyst, the reaction leads to the formation of an ester. This is a typical esterification reaction, where the hydroxyl group is replaced by the alkoxy group.
Step 2: Recognize the product.
The product will be an ester, where the phenolic hydroxyl group (\( \text{OH} \)) is replaced by an alkoxy group (\( \text{OR} \)), resulting in \( \text{Ar-O-R} \).
Step 3: Final conclusion.
Thus, the product formed in this reaction is:
\[
\boxed{\text{(1) } \text{Ar - O - R}}
\]