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A2 chemistry unit 4 mock tomorrow!

can anyone help with this question?:

an aldehyde has the molecular formula C5H10O.

Its h nmr spectrum contains a doublet at delta= 0.9ppm with relative peak area of 6 compared with the aldehyde proton.

analyse this information to deduce the structure of the aldehyde. explain your reasoning

thanks :smile:
Original post by Princess_perfect786
can anyone help with this question?:

an aldehyde has the molecular formula C5H10O.

Its h nmr spectrum contains a doublet at delta= 0.9ppm with relative peak area of 6 compared with the aldehyde proton.

analyse this information to deduce the structure of the aldehyde. explain your reasoning

thanks :smile:


relative peak (compared to CHO) are means there are six equivalent hydrogen atoms...

any ideas?
Original post by charco
relative peak (compared to CHO) are means there are six equivalent hydrogen atoms...

any ideas?


oh yeah... benzene.

but wouldn't there only be 5 equivalent h atoms because the CHO group has replaced one of them?
(edited 13 years ago)
Original post by Princess_perfect786
oh yeah... benzene.

but wouldn't there only be 5 equivalent h atoms because the CHO group has replaced one of them?


There are only five carbons in total!!!! How can is be C6H5- ?

The only way you can have six equivalent hydrogens is two -CH3 groups. If these form a doublet then they're both adjacent to a CH...

Try again
Original post by charco
There are only five carbons in total!!!! How can is be C6H5- ?

The only way you can have six equivalent hydrogens is two -CH3 groups. If these form a doublet then they're both adjacent to a CH...

Try again


the closest i can get is:

(ch3)ch(ch3)cho i don't know how to get the other carbon and other three hydrogens
Reply 5
Avatar for sssm
sssm
1
isnt it
c double bond o for the aldehyde group at the end, the ch2 and then a c with 2 methyl groups and 1 h attached to it :/
Reply 6
Avatar for sssm
sssm
1
so altogether there is 4 environments. i thinkk
Original post by sssm
isnt it
c double bond o for the aldehyde group at the end, the ch2 and then a c with 2 methyl groups and 1 h attached to it :/


i think that's right. thanks :smile:
Reply 8
Avatar for jlcf
jlcf
1
So is the answer 3-methylbutanal?
Reply 9
Avatar for sssm
sssm
1
i think its 3-methylbutanal

yup :smile:
i think thats what the answer is.
Reply 10
Avatar for sssm
sssm
1
wouldnt it be 2methylbutanal.
if your counting so its the smallest number is would be 2 right?
Reply 11
Avatar for jlcf
jlcf
1
http://www.docbrown.info/page15/Image1896.gif
3 methyl butanal

http://www.docbrown.info/page15/Image1894.gif
2 methyl butanal

i think it is 3 methyl butanal, you count from the functional group?
(edited 13 years ago)
Reply 12
Avatar for sssm
sssm
1
i defo got the one under 3 methyl butanal.
The important thing is to understand why...

(CH3)2CHCH2CHO

Do you?

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