Protocol for Practical Classes

Subject: pH and buffers

Experiment 3 – Carbonic acid

Materials:

An assay tube;

A pippete;

Bromothymol Blue 20% in water.

Metods:

In a assay tube with the Bromothymol blue insert an empty pippete and blow it alowly, expelling the bubles inside the solution.

Write down the result.

Objectives:

To caractherize color pH indicators.

To see the color variation on a indicator, following the pH changes.

Report suggestions:

Identify the Bromothymol blue as a pH indicator

Explain how and why the solution has changed its color.

Exlain the importance of this buffer system to biological systems.