Tests for Functional Groups

Neutral $FeCl_3$ gives a violet colour with phenols; correct.
Fehling's solution is reduced by glucose (a reducing sugar) to a red precipitate of $Cu_2O$; correct.
Sodium bisulphite forms crystalline addition products with aldehydes and many ketones; correct.
Tollens' reagent (ammoniacal silver nitrate) is used to detect aldehydes (silver mirror test), not unsaturation. Unsaturation (C=C) is detected with bromine water or Baeyer's reagent (cold dilute alkaline $KMnO_4$).
So the incorrect statement is that Tollens' reagent is used in detection of unsaturation.