Tollens' test is a qualitative test used to distinguish between aldehydes and ketones. The reagent used in this test is Tollens' reagent, which is a solution of silver nitrate (AgNO₃) in aqueous ammonia (NH₃).
Outcome of Tollens' Test:
- Positive Result (for Aldehydes): If an aldehyde is present, it will reduce the silver ion (Ag⁺) in Tollens' reagent to metallic silver (Ag). This is typically observed as a silver mirror forming on the walls of the test tube or as a gray precipitate of silver.
- Negative Result (for Ketones): Ketones generally do not react with Tollens' reagent, so there will be no color change or formation of silver mirror.
In summary, a positive Tollens' test indicates the presence of an aldehyde functional group, while a negative result suggests the absence of an aldehyde (and most likely the presence of a ketone or other compound).
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