Functional Group Tests
Test Rack
Step 1: Choose a test reagent. Step 2: Choose an unknown sample. Observe the result.
Results Table
Identification Progress
About Functional Group Tests
Functional group tests are qualitative analytical techniques used to identify the type of organic compound in a sample. Each test reagent reacts with specific functional groups, producing visible changes such as colour changes, precipitates, or mirror formation.
Brady's reagent (2,4-DNPH) forms an orange precipitate with aldehydes and ketones (compounds containing a carbonyl group). Tollens' reagent (silver mirror test) is reduced by aldehydes to form metallic silver, but not by ketones. Bromine water is decolourised by alkenes (C=C double bonds). Acidified potassium dichromate oxidises primary and secondary alcohols, changing from orange to green.
By combining the results of multiple tests, you can systematically identify unknown organic compounds: a positive Brady's + positive Tollens' = aldehyde; positive Brady's + negative Tollens' = ketone; positive bromine water = alkene; positive dichromate = alcohol.