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How to count carbon environments

Can anyone please explain why carbon 1 and carbon 2 are two different environments? I am not really sure which part of the molecule you look at to determine it. Thanks 1234.png
Reply 1
Avatar for alow
alow
19
Original post by coconut64
Can anyone please explain why carbon 1 and carbon 2 are two different environments? I am not really sure which part of the molecule you look at to determine it. Thanks 1234.png


One is ortho to the -OH, the other is meta. Therefore they are in different environments.
Reply 2
Avatar for coconut64
coconut64
OP
16
Original post by alow
One is ortho to the -OH, the other is meta. Therefore they are in different environments.


This is just A-level chemistry, so the spec doesn't really require us to know much about meta or ortho. I was told that you just look for the line of symmetry but how?

thanks
Reply 3
Avatar for rose:)
rose:)
8
Carbon 1- the carbon to the left has an alcohol attached. Carbon 2- the carbon to the right just has hydrogens attached
Reply 4
Avatar for alow
alow
19
Original post by coconut64
This is just A-level chemistry, so the spec doesn't really require us to know much about meta or ortho. I was told that you just look for the line of symmetry but how?

thanks


Ortho means the substituent is next to whatever group you're referring to, meta means it's got one carbon between them and para means they're on opposite sides.
Reply 5
Avatar for 1256601
1256601
9
Original post by alow
Ortho means the substituent is next to whatever group you're referring to, meta means it's got one carbon between them and para means they're on opposite sides.


i guess I having more sophisticated answers, thanks, never knew this existed
Reply 6
Avatar for alow
alow
19
Original post by thatawesomekid
i guess I having more sophisticated answers, thanks, never knew this existed


Yeah it's a lot more common to use o/m/p to describe directing groups and substitutions than using the numbering of carbons when you get past A Level.
Original post by coconut64
Can anyone please explain why carbon 1 and carbon 2 are two different environments? I am not really sure which part of the molecule you look at to determine it. Thanks 1234.png


If you imagine the same molecule but without the OH group, then you can see it has a plane of symmetry running across the molecule, this would make carbons 6 and 7 equivalent, carbons 5 and 8 equivalent, carbons 3 and 4 equivalent and carbons 1 and 2 equivalent. Hopefully that helps you see the sort of symmetry to look for when trying to spot equivalent carbons. Adding the OH means the molecule loses this symmetry so the carbons are no longer equivalent! :smile:
(edited 7 years ago)
Reply 8
Avatar for coconut64
coconut64
OP
16
Original post by MexicanKeith
If you imagine the same molecule but without the OH group, then you can see it has a plane of symmetry running across the molecule, this would make carbons 6 and 7 equivalent, carbons 5 and 8 equivalent, carbons 3 and 4 equivalent and carbons 1 and 2 equivalent. Hopefully that helps you see the sort of symmetry to look for when trying to spot equivalent carbons. Adding the OH means the molecule loses this symmetry so the carbons are no longer equivalent! :smile:


thanks
Original post by coconut64
thanks


No problem :smile:

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