Chemistry - GOC Question with Solution | TestHub

Removing H₁ gives the imine anion :

Removing H₂ gives the ring carbanion :

The imine anion has its lone pair in an sp2 orbital lying in the plane of the ring, orthogonal to the π system, so the charge stays localised. The ring carbanion sits next to the C=N π bond and delocalises onto the exocyclic nitrogen, like an aza-enolate. Delocalisation beats the atom comparison here, so H₂ is more acidic.