Basics of this experiment

In this experiment, the fundamental principles of electrolysis are conveyed. The goal of this experiment is the electrolytic generation of hydrogen. To achieve this, the specific conductivity of three different water samples (water from Stadtwerke Essen, fully desalinated water from the University of Duisburg-Essen Campus Essen, and Millipore water processed in the physical chemistry department of the University of Duisburg-Essen) is measured using a conductivity meter (InoLab Cond 7110).

To enhance the conductivity, a salt of your choice is added as a conducting salt, and the specific conductivity is measured again at various concentrations.

Dissociation of salts:

Review the basics of the strength of chemical bonds before conducting the experiment.

• Units of chemical bond energy
• Bond energies in organic and inorganic chemistry

Why do salts dissociate?"

Electrolysis in experiment

With the electrolyte solution you discuss with your supervisor, an electrolysis is then performed in a Hofmann voltameter, resulting in the production of hydrogen.

Which gases can be generated at the anode? Would you like to determine the pH values of the anode and cathode spaces? This is optional! Are there any discolorations in the two electrolyte chambers?

Let's delve into the gas production in detail. Upon closer inspection, you'll notice that the gases in the anode and cathode chambers differ.

Take a look in the literature to understand how the solubility of hydrogen, oxygen, and carbon dioxide in water differs. It's also noticeable that the bubbles in the anode and cathode chambers are of different sizes. Hhmm?"

Purified water

In the following publication, you will find the basic properties of ultrapure water here.

However, this concerns highly pure water; just take a look at Figure 1 and the elaborate pretreatment of the water.

You can find the properties of our Millipore water here. This Wikipedia article also explains why Millipore water in laboratory practice might have a higher conductivity than 0.055 micro S/cm.

Dear students,

this is only an example. May be you get a smell.