Experiment 64

Objective

To identify phenol using a reaction with neutral ferric chloride, which produces a characteristic violet color.

Introduction

Phenol reacts with neutral ferric chloride (FeCl₃) to form a violet-colored complex, identified as diferric hexaphenate. This color change is a classic qualitative test for phenol.

Materials

Chemicals

●      Phenol

●      Ferric chloride (FeCl₃)

Apparatus

●      Test tube

●      Test tube holder

●      Thermometer

●      Tissue paper

●      White paper for color observation

Reagents

●      10 mL of phenol with 2-3 drops of neutral ferric chloride solution

Procedure

1.    Preparation of Test Solution

o   Place phenol in a test tube.

2.    Addition of Ferric Chloride

o   Add 2-3 drops of neutral FeCl₃ to the phenol sample.

3.    Mixing and Observation

o   Shake the sample gently and allow the reaction to proceed for a few moments.

4.    Color Determination

o   Observe the color change, using a white paper background to clearly see the violet hue.

Observation

A violet color appears in the solution, indicating the formation of the diferric hexaphenate complex, confirming the presence of phenol.

Questions

1.    What is the color of the diferric hexaphenate complex?

2.    Why is neutral ferric chloride solution used?