Quick Ochem Question

[StudentDoc1234]

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Hi everyone,

I was wondering where would a para-nitrophenol rank in terms of acidity compared to these compounds? The order of these from least acidic to most acidic are: II<IV<III<I

 

[510586]

Wouldn't it be the most acidic because it's the strongest electron withdrawing group? Tough to say since it is farther away though..

 

[StudentDoc1234]

Not sure, I think compound I would still be more acidic.

 

[510586]

Not sure, I think compound I would still be more acidic.

This seems like those 1 or 2 crazy ones they throw on the DAT to separate the 30s from the pleb 29s haha

 

[FeralisExtremum]

I would expect para-nitrophenol to be the most acidic.

 

[StudentDoc1234]

Okay ya the extra resonance structure p-nitrophenol provides would make it the most acidic. Thanks guys!

 

[DAT Destroyer]

Hi everyone,

I was wondering where would a para-nitrophenol rank in terms of acidity compared to these compounds? The order of these from least acidic to most acidic are: II<IV<III<I

View attachment 193154

Guys...I HATE to spoil this party......BUT......The 2,5-difluorophenol would easily win. YES.....OUR BELOVED NITRO almost never loses when it comes to acidity.....but ALAS.....2 fluorines in close proximity to the OH is the kiss of death. Why ? Well....the anion is more stabilized......both ,by an inductive effect.....and some resonance,,,,,,but induction is more important here. The pKa of the para-nitrophenol is about 7......The 2, 5-difluorophenol.....about 4 or. 5.

Nothing to this extent will appear on the DAT,,,,,,But this is a nice question for Grad students or my Advanced Organic Chemistry students.

REMEMBER,,,,,,,when it come to acidity.....STABILIZE THY ANION !!!!!


Hope this helps

Dr. Romano