Textbook 6.21

[Emily Hou 1H]

The two strands of the nucleic acid DNA are held together by hydrogen bonding between four organic bases. The structure of one of these bases, thymine, is shown below. (a) How many protons can this base accept? (b) Draw the structure of each conjugate acid that can be formed. (c) Mark with an asterisk any structure that can show amphiprotic behavior in aqueous solution.
For this question, why can't the O atoms also accept protons?

[MattDixon3A]

Hi, since Oxygen is more electronegative than Nitrogen, it's unlikely to share electrons, as it would give Oxygen a positive charge, which would make the molecule less stable. I hope this helps!