Experiment 21

Objective

To differentiate between phenol and acetic acid using sodium bicarbonate.

Introduction

Both phenol and acetic acid are acidic, but they differ in their reactivity with sodium bicarbonate (NaHCO₃). Acetic acid reacts with sodium bicarbonate, producing carbon dioxide gas, observable as bubbles, while phenol does not react. This characteristic allows for a straightforward differentiation between the two compounds.

Reaction:

CH3​COOH + NaHCO3 ​→ CH3​COONa + H2​O + CO2​↑

Materials

Chemicals

●      Phenol

●      Acetic acid

●      Sodium bicarbonate

Apparatus

●      Two test tubes

●      Two test tube holders

●      Dropper

Reagents

●      5% sodium bicarbonate solution

●      5 ml of each sample (phenol and acetic acid)

Procedure

1.    Place 5 ml of phenol in one test tube and 5 ml of acetic acid in another test tube.

2.    Secure each test tube in its holder.

3.    Add the 5% sodium bicarbonate solution dropwise to each test tube.

4.    Observe any reactions in each test tube.

Observation

In the test tube containing acetic acid, carbon dioxide bubbles form, indicating the production of CO₂. In the test tube containing phenol, no reaction is observed.

Questions

1.    How can acetic acid and phenol be differentiated?

2.    Why does phenol not react with sodium bicarbonate?

3.    Why does acetic acid react with sodium bicarbonate?