# Acidity of substituted phenols

by maverick280857
Tags: acidity, phenols, substituted
 P: 1,770 Hello again My question: Rank the following compounds in order of decreasing acidity: (a) phenol (b) o-nitrophenol (c) m-nitrophenol (d) p-nitrophenol I know that (d) will be most acidic. But here's the problem: in orthonitrophenol the hydrogen of the -OH group satisfies the conditions for intramolecular hydrogen bonding and should in theory be bound to the nitrogen of the nitro substituent making difficult its loss as H+. So (c) should be more acidic than (b). 1. Is this reasoning correct? 2. Is o-nitrophenol more acidic than phenol despite the above reasoning (if at all the above reasoning is correct)? 3. What is the actual order of acidity. I would be grateful if someone could help me out with this because I have two contradicting answers. Thanks and cheers Vivek
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 Quote by maverick280857 Rank the following compounds in order of decreasing acidity: (a) phenol (b) o-nitrophenol (c) m-nitrophenol (d) p-nitrophenol
Hello, I will turn the question upside down again Don't worry, somebody will help us

If we want a phenol-based acid to be strong, we must decrease the electronic density in the benzene ring. Thus, o- and p-nitrophenols have some "relief" because of their positions; however, m-nitrophenol is sufficiently electron deficient, so I presume that this one should be the most acidic one. Later comes phenol, as the others possess increased electron flow through the ring. The p-derivative is sterically very relieved, so this should be the least acidic one.

According to my reasoning, the final order is likely to be as follows:

$$m-nitrophenol > phenol > o-nitrophenol > p-nitrophenol$$
 Sci Advisor HW Helper P: 1,769 m-nitro phenol is actually lower is acidity than p or 0 nitro-phenol. Based on this, I'm sure you can finish up this question (which is more acidic, phenol or m-nitrophenol?). I apologize if I sounded condenscending.
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