Which ketones gives a positive Tollen's test ?

Alpha hydroxy ketones are gives positive Tollen's test because tauotomerise into aldehyde .

Related Questions:

Penta-1,3-diene is more stable than penta-1,4 -diene. Why?

Phenoxide ion is more stable than an alkaoxide. why?

Why does aqueous sodium bicarbonate solution dissolve carboxylic acids but not phenol though they are also acidic ?

Why enol form of Beta Dicarbonyl compound more stable than those of monocarbonyl compounds?

Why enol form of phenol is more stable than its keto isomers?

Reactivity order of Pyrrole, Furan and Thiophene towards Electrophilic substitution :

Phenyl group is known to extract negative inductive effect, but each phenyl ring in biphenyl is more reactive than benzene towards Electrophilic substation. Why?

Chloroform is more acidic than fluoroform why?

Fluorine is more electronegative than chlorine even then, p-flurobenzoic acid is weaker acid than p-chlorobenzoic acid explain ? 

Trifluoroethyl carbocation is less stable than trifluromethyl carbocation why ?

Why is the Tropylium carbocation less stable than the tricyclopropylmethyl carbocation?