Molisch & Fehling Tests: Comparing Results

Thread starter spacetime
Start date Oct 26, 2004

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SUMMARY

The discussion focuses on the relationship between the Molisch test and Fehling's test in organic chemistry. A positive Molisch test indicates the presence of carbohydrates, while a negative Fehling's test confirms the absence of oxidizable groups, particularly aldehydes. Compounds such as ketones or certain polysaccharides may yield a positive Molisch test without reacting in Fehling's test. Understanding these tests is crucial for identifying specific functional groups in organic compounds.

PREREQUISITES

Knowledge of organic chemistry functional groups
Understanding of carbohydrate chemistry
Familiarity with qualitative analysis techniques
Experience with laboratory testing methods

NEXT STEPS

Research the specific reactions involved in the Molisch test
Study the limitations of Fehling's test in organic compound identification
Explore the chemical structure of common carbohydrates
Learn about alternative tests for detecting aldehydes and ketones

USEFUL FOR

Chemistry students, organic chemists, laboratory technicians, and anyone involved in the qualitative analysis of organic compounds.

Oct 26, 2004

spacetime

Hey, what could be a compund that gives a positive Molisch test but a negative fehling's test?

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Oct 26, 2004

chem_tr

Science Advisor

Gold Member

Hello, I haven't remembered what is the Molisch test, but a negative Fehling's test indicates that the compound does not have any oxidizable group, especially the aldehyde one.

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