Question

What is Bial’s test?

Answer 1

Bial’s test:

• It is a chemical test to detect the presence of pentoses.
• The components for this test are orcinol, hydrochloric acid, and ferric chloride.
• This test is based on the principle in which pentoses are dehydrated into furfural which in turn condense with orcinol to give a blue-green precipitate or bluish precipitate.
• The chemical equation is as follows:

Indication of test:

• A positive test for pentoses is indicated by the formation of a bluish precipitate.
• A negative test is indicated by the formation of all other colours.