Step 1: Understanding the Question:
This is a qualitative identification test for functional groups. The question asks for the observation when phenol is treated with \(\mathrm{FeCl_3}\). Step 2: Detailed Explanation:
The addition of neutral ferric chloride (\(\mathrm{FeCl_3}\)) to phenol leads to the formation of a coordination compound.
The phenoxide ions act as ligands that coordinate with the \(Fe^{3+}\) ion.
The reaction can be represented as:
\[ \mathrm{6 C_6H_5OH + FeCl_3 \rightarrow [Fe(OC_6H_5)_6]^{3-} + 3H^+ + 3HCl} \]
The resulting complex, ferric phenoxide, possesses a characteristic deep violet or purple color.
This test distinguishes phenols from alcohols (which do not show this color change). Step 3: Final Answer:
The reaction produces a violet colored complex.