Solubility of N-[(4-hydroxy-3-methoxyphenyl)methyl]acetamide at different pH The molecule below is a simplified analog of capsaicin. Explain in which of the following options, it should be most soluble:
  
  
  aqueous HCl (pH = 1)
  aqueous NaOH (pH = 14)
  pure water (pH = 7)
  
  
  
  N-[(4-hydroxy-3-methoxyphenyl)methyl]acetamide, National Center for Biotechnology Information. PubChem Compound Database; CID=606880


I chose aqueous NaOH, because then the molecule will be completely deprotonated, which will make it more soluble. Please tell me if this is correct.
I would agree that it is most soluble in NaOH.

However, the molecule will only deprotonate the OH proton not the NH proton.  I wouldn't give your explanation much, if any, credit because you aren't saying which proton would deprotonate, and you are implying the molecule will lose all protons.

Also, at low enough pH the N will protonate, i.e. it would gain a second proton.