Hd is more acidic because Carbanion is resonating with C=O, while in case of He, it ia resonating with C=NH. here O is more EN than N so effective resonance is present in case of H...
better resonance in the carbanion formed from Hd than He...From Hd resonance is with C=O group...better resonance and from He resonance with C=Nh not better resonance than C=O as O...