Chemistry - GOC Question with Solution | TestHub

Removing H₁ puts the negative charge on the amino nitrogen :

Removing H₂ puts the negative charge on the amide nitrogen :

In the first conjugate base the charge is localised on nitrogen. In the second, the charge is delocalised by resonance over the amide nitrogen and the carbonyl oxygen. A delocalised charge is more stable, so the second conjugate base wins and the amide N-H proton H₂ is more acidic.