How do qualitaitve analysis work?

[jd12345]

I usually see a specific functional group is reacted with a transition metal to forma complex producing bright colours - and we distinguish groups based on such reactions and colours

But the complex will be formed with any nucleophile ( ligand ) right?. Example:- cerric ammonium test is done for alcohols. IT forms a complex with alcohol as the the -OH group acts as a ligand producing red colour.
But this red colour will be formed with any nucleophile as any other ligand can form the complex.

Same with other functional groups. I don't see how complex formation distinguishes these functional groups

 

[Borek]

Different ligands produce different colors (please read about crystal field theory), correctly selecting the transition metal and conditions it is possible to make the reaction quite specific.

But I suppose false positives are possible in some cases.