sciencegod

Super Member
10+ Year Member
Nov 20, 2008
198
0
Status
Pre-Dental
guys what's more acidic phenol or c6h5NH3+ with a no2 attached to para posiiton.
 

sciencegod

Super Member
10+ Year Member
Nov 20, 2008
198
0
Status
Pre-Dental
the nh3+ on ring has no resoannce structures yet kaplan says its mpre acidic.
 
About the Ads

montag925

10+ Year Member
Dec 29, 2006
91
1
New Jersey
Status
Dental Student
by rule of thumb, and for the simplicity of any question asked on the DAT:
the more electron withdrawing a group on a benzene ring is, the more acidic it will be...on the contrary, the more electron donating, the more basic.
to break it down even down farther, H+ groups (such as those in NH3) are elctron withdrawing, as compared to -OH which is electron withdrawing, but not to the same extent.
 

joonkimdds

Senior Member
10+ Year Member
7+ Year Member
Jun 30, 2005
2,780
2
Status
Pre-Dental
shouldn't answer be phenol since NO2 from the other one is electron donating and that's counteracting against electron withdrawing to make it less acidic?

By the way, how do we know which electron withdrawing is more electron withdrawing (more acidic) than the other?
do we have to memorize strongly, moderately, weakly activating/deactivating or is there an easy way to understand the concept:?
 

sciencegod

Super Member
10+ Year Member
Nov 20, 2008
198
0
Status
Pre-Dental
by rule of thumb, and for the simplicity of any question asked on the DAT:
the more electron withdrawing a group on a benzene ring is, the more acidic it will be...on the contrary, the more electron donating, the more basic.
to break it down even down farther, H+ groups (such as those in NH3) are elctron withdrawing, as compared to -OH which is electron withdrawing, but not to the same extent.
don't think your right. electron donating and withdrawing have nothing ti do with the acidit.y all it could do is if its a secong substituent on a ring it would stabilize the anion but not if its the only substituemt. that would have nothing to do with acititudy or basicity.
 

sciencegod

Super Member
10+ Year Member
Nov 20, 2008
198
0
Status
Pre-Dental
http://forums.studentdoctor.net/archive/index.php/t-411177.html

That should answer your question. The electron withdrawing groups stabilizes the ring making it more acidic through inductive effect.
you people seem to not be understanding something. when an acidic gorup has also a withdrawing group on the benzene it makes it more acidic. understood. myh question was in terms of the acidic group itself. that has nothing at all to do with whethere it is electron donating or withdrawing imo.

doesnt anyone understand what im saying.:eek:
 

nhpham2

10+ Year Member
5+ Year Member
Oct 10, 2008
18
0
Status
c6h5NH3+ would be more acidic. And c6h5NH3+ actually has 3 resonance structure if you push the carbocation onto the benzene ring.

you people seem to not be understanding something. when an acidic gorup has also a withdrawing group on the benzene it makes it more acidic. understood. myh question was in terms of the acidic group itself. that has nothing at all to do with whethere it is electron donating or withdrawing imo.

doesnt anyone understand what im saying.:eek:
 

sciencegod

Super Member
10+ Year Member
Nov 20, 2008
198
0
Status
Pre-Dental
c6h5NH3+ would be more acidic. And c6h5NH3+ actually has 3 resonance structure if you push the carbocation onto the benzene ring.
there's no carbocation . were talking about what is most stable after it loses the H. (if it were very stable in its current form with + it would not be acidic at all bec wouldn lose H).
 

nhpham2

10+ Year Member
5+ Year Member
Oct 10, 2008
18
0
Status
Well judging by pka alone. The anilinium would still be more acidic with a pka of 4.6 and the phenol is at 10. The NO2 group would just make it more acidic.

there's no carbocation . were talking about what is most stable after it loses the H. (if it were very stable in its current form with + it would not be acidic at all bec wouldn lose H).
 

joonkimdds

Senior Member
10+ Year Member
7+ Year Member
Jun 30, 2005
2,780
2
Status
Pre-Dental
if e- withdrawing is what makes the ring more acidic, and e- donating does the oppsite, shouldn't phenol be more acidic since the other one has e- donating but phenol doesn';t have.
 

gentile1225

10+ Year Member
5+ Year Member
May 12, 2008
383
0
New York
Status
Pre-Dental
any electron withdrawing group on the ring increases the acidity as already stated above. no2 is very deactivating and highly electron withdrawing. also, whenever you have a meta director in the o,p position you highly increase the acidity. draw out the resonance forms.

hope this helps.
 
About the Ads