[timchai]

Owing to resonance stabilization of the conjugate base, an α-hydrogen in an aldehyde is more acidic than a hydrogen atom in an alkane
i forget it . can u draw the resonance structure when H+  removed ,

[macman104]

No, we cannot.  You need to try all of these questions that you are posting before you post them.  You need to show attempts or at least explain what you don't understand.