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I have determined one of my unknowns to be benzophenone and in a lab setting (but that isn't possible because of COVID-19) I would conducted the 2,4 DNP test which should yield a positive result. However, I am a bit stuck on other tests that would make it very definitive that a ketone is present.

I know if I use the following test, I would get the following results:

  1. The Tollen's test- it would be negative because an aldehyde isn't present
  2. The iodoform test- would be negative because the ketone on benzophenone would be negative
  3. The Chromic Acid test- would be negative because Aldehydes are oxidized by chromic acid, ketones are not.

But are there any other tests that can be used?

I have seen the previous post on this question dated back to 4 years ago and it didn't really help.

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  • $\begingroup$ It would give negative Schiff's test, Benedict and Fehling's test. $\endgroup$ – Zenix May 6 at 21:26
  • $\begingroup$ Take an mp of sublimed material (benzophenone, mp 48.5oC). Reduce with NaBH4 to benzhydrol (mp. 69oC). Dissolve unknown in anhydrous THF under nitrogen. Add sodium. Blue sodium benzophenone ketyl forms. $\endgroup$ – user55119 May 7 at 0:15
  • $\begingroup$ Not really, I had seen that post. $\endgroup$ – Boo May 7 at 19:38