On melting, sodium carbonate decomposes and thereby reacts with the sulphur present in organic substances under the formation of brown coloured sodium polysulphides. The colour of these polysulphides is similar to that of liver, and this is the basis for the name "Hepar test", Hepar being Greek for liver. Soluble polysulphides form silver sulphide spontaneously with  metallic silver. Proteins with a high content of cysteine or methionine are particularly rich in sulphur. These include the vegetable proteins in the fruits of leguminous plants.

Learning objectives

• Many organic substances, proteins in particular, contain sulphur.
• Sulphur can be detected as silver sulphide (Hepar test).

Benefits

• Easy teaching and efficient learning by using interactive experimentation PHYWE-Software
• Experiment is part of a complete solution set with experiments for the topic Organic Chemistry matched with international curriculum: all topics are covered