I\'m trying to study IR spectrum here, how can we determine how many carbons are there in an unknown compound. like we define a alcohol functional group, but how can we tell the difference between for example heptane and hexane? I can find all the functional groups, but to name the structure, i cannot because i don\'t know how many carbons i have. Need this asap as i have a quiz in a few hours! Solution Only IR is not enough to differentiate between heptane and hexane. IR not gives information about number of carbons in the structure, it tell about the functional group. For such study we need another supportive tool like 1H NMR or 13C NMR. So as per my understanding its not possible to do the task with IR. .

1. I'm trying to study IR spectrum here, how can we determine how many carbons are there in an
unknown compound. like we define a alcohol functional group, but how can we tell the
difference between for example heptane and hexane? I can find all the functional groups, but to
name the structure, i cannot because i don't know how many carbons i have. Need this asap as i
have a quiz in a few hours!
Solution
Only IR is not enough to differentiate between heptane and hexane. IR not gives information
about number of carbons in the structure, it tell about the functional group. For such study we
need another supportive tool like 1H NMR or 13C NMR.
So as per my understanding its not possible to do the task with IR.