3. In the paper by Leopold and his students, one of the justifications for the study was the relationship of the zwitterion to sulfamic acid. Sulfamic acid is a solid at room temperature. Suggest a reason why this is so, based on bonding interactions.

Sulfamic acid is H₂N-SO₃H, which as well set up for hydrogen bonding from the acidic hydrogen to either O or N lone pairs on adjacent molecules. The solid probably has a network of H-bonds.