Tollen's Test with Salicylaldehyde
Of course, the answer is resonance.  As described by Benet et al., a basic medium (pH&gt;10) favours the Tollen's reaction. On the other hand, if we want to dissolve phenol in water, we will need OH- to generate phenolate. It means the hydroxyl group of salicylaldehyde is sensitive to the high pH, and this hinders attacking the other hydroxides to the carbonyl group by further stabilizing it.