Between two oxyacids with different heteroatoms, the one with the more ________ heteroatom is more acidic.

Between two oxyacids with different heteroatoms, the one with the more ________ heteroatom is more acidic.

• A. Electronegative
• B. Atomic mass
• C. Size
• D. Position in periodic table

Answer: (A)

Acidity in oxyacids hinges on how well the conjugate base can bear and distribute the negative charge after deprotonation. When the proton is removed, the resulting oxyanion carries the negative charge, which is stabilized by withdrawing electron density from the rest of the molecule. A more electronegative heteroatom pulls electron density away more effectively, stabilizing that negative charge through inductive effects and resonance with the oxygens. That stabilization makes deprotonation more favorable, so the acid is stronger. So the acid with a more electronegative heteroatom is the stronger one. The other options—mass, size, or position in the periodic table—do not directly determine how well the conjugate base is stabilized in this context.

Acidity in oxyacids hinges on how well the conjugate base can bear and distribute the negative charge after deprotonation. When the proton is removed, the resulting oxyanion carries the negative charge, which is stabilized by withdrawing electron density from the rest of the molecule. A more electronegative heteroatom pulls electron density away more effectively, stabilizing that negative charge through inductive effects and resonance with the oxygens. That stabilization makes deprotonation more favorable, so the acid is stronger.

So the acid with a more electronegative heteroatom is the stronger one. The other options—mass, size, or position in the periodic table—do not directly determine how well the conjugate base is stabilized in this context.