hNMR question

[Questions]

Advertisement - Members don't see this ad

in achiever. there is a quesion about p-xylene. can someone explain why only 2 singlets would show up?
thanks

 

[hausee]

in achiever. there is a quesion about p-xylene. can someone explain why only 2 singlets would show up?
thanks

It is a symmetric molecular only have two kind of equivalent hydrogen. 6 hydrogen(singlet) on methyl group and 4 on benzene(doublet).

m-xylene will have 4 peak (6-H on methyl, one between two methyl and one opposite to it, and the rest two, which give out singlet, singlet, triplet and doublet respectively.)


and o-xylene will have 3 peak (6-H on methyl, two near methyl groups and two further away from methyl groups, Which give out singlet, doublet, triplet respectively)

Correct me.

 

[sfoksn]

After looking up how p-xylene looked like I could undrstand.

Hausee, you are correct.

Well, are we expected to know all the special names like that?

Why couldn't they just say p-toluene?

 

[hausee]

I guess so. I remember I saw them somewhere in the old ADA test. They just want to show off you know. :S

After looking up how p-xylene looked like I could undrstand.

Hausee, you are correct.

Well, are we expected to know all the special names like that?

Why couldn't they just say p-toluene?

 

[sfoksn]

does anyone know a resource that contains all the common names that we should know for DAT? 🙁

 

[Questions]

It is a symmetric molecular only have two kind of equivalent hydrogen. 6 hydrogen(singlet) on methyl group and 4 on benzene(doublet).

m-xylene will have 4 peak (6-H on methyl, one between two methyl and one opposite to it, and the rest two, which give out singlet, singlet, triplet and doublet respectively.)


and o-xylene will have 3 peak (6-H on methyl, two near methyl groups and two further away from methyl groups, Which give out singlet, doublet, triplet respectively)

Correct me.

Then for m-xylene, isn't there a plane of symmetry like in p-xylene?
so wouldn't it be less than 4?

 

[redchesus]

you can draw lines of symmetry for all of them