Chemistry - GOC Question with Solution | TestHub

Removing H₁ puts the negative charge on sulphur :

Removing H₂ puts the negative charge on oxygen :

Oxygen and sulphur are in the same group, so the deciding factor is size. Sulphur is larger than oxygen, so the negative charge is spread over a larger volume and the thiolate is more stable than the alkoxide. The S-H proton H₁ is more acidic.