Ochem+Gchem Q's pls help!

[kayo]

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I am reviewing TS and achiever right now.
Here are questions/ some parts of the questions I don't really understand...

1. H NMR on 1,4-dimethylbenzene
On achiever, it has 2 singlets. Ok, first singlet is due to methane groups.
So the second singlet is from benzene right?
I guess all the H's from benzene are equal in this case.
How about H NMR on 1-chloro 2methyl benzene?
Are all H's on benzene still same?

2. are they R/S configurations?
CH3 Br C00H
! ! !
Br-C-H F-C-CHO CH3-C-F
! ! !
COOH H NH3

Answer- R, S, S respectively.
Groups with bigger atomic # has higher priority.(assigned #)
so 1st one has priority in the order Br>COOH>CH3(going counterclockwise
but H is between CH3 and COOH(3rd priority) so
going clockwise..R?
I did the same method for the 2nd and 3rd ones, too.
But I got R, R, R configuration..

3) Is it possible to know Zn is gonna be reduced if given
the condition that Zn and Cu are in electrolysis?

I thought reduction potential for that.
Do u guys have any clues?

Thanks! 👍

 

[who knows...]

I am reviewing TS and achiever right now.
Here are questions/ some parts of the questions I don't really understand...

1. H NMR on 1,4-dimethylbenzene
On achiever, it has 2 singlets. Ok, first singlet is due to methane groups.
So the second singlet is from benzene right?
I guess all the H's from benzene are equal in this case.
How about H NMR on 1-chloro 2methyl benzene?
Are all H's on benzene still same?



Thanks! 👍

Here is a GREAT NMR/IR site...you can type in WHATEVER formula you want...and it will tell you everything...what each singlet/doublet/triplet...etc is coming from...and ...it will just tell you everything you need...check it out...
im positive it will help...
http://www.aist.go.jp/RIODB/SDBS/cgi-bin/cre_index.cgi
oh yeah...just click the "I agree ..." first to enter the site! Enjoy!
and here is another very good link:
http://w3.chem.ucla.edu/~webspectra/

 

[who knows...]

2. are they R/S configurations?
CH3 Br C00H
! ! !
Br-C-H F-C-CHO CH3-C-F
! ! !
COOH H NH3

Answer- R, S, S respectively.
Groups with bigger atomic # has higher priority.(assigned #)
so 1st one has priority in the order Br>COOH>CH3(going counterclockwise
but H is between CH3 and COOH(3rd priority) so
going clockwise..R?
I did the same method for the 2nd and 3rd ones, too.
But I got R, R, R configuration..

Im getting r r r too 🙁

 

[kayo]

Here is a GREAT NMR/IR site...you can type in WHATEVER formula you want...and it will tell you everything...what each singlet/doublet/triplet...etc is coming from...and ...it will just tell you everything you need...check it out...
im positive it will help...
http://www.aist.go.jp/RIODB/SDBS/cgi-bin/cre_index.cgi
oh yeah...just click the "I agree ..." first to enter the site! Enjoy!
and here is another very good link:
http://w3.chem.ucla.edu/~webspectra/

Thanks for the links!
I guess the bottomline is equivalent H's dont split each other.
Let me know when you find out how to solve other q's! 😉

kayo