Part 6: SPECTROSCOPY (in reality...)

The following data is available from the question:

MS: M = 198 / 200 (this shows the characteristic isotope pattern for a Br)

EA: The % data when used together with the MW allows one can get the molecular formula = C9H11Br, . From here we get the IHD = 4 which is quite high and suggests that we should consider benzene systems....

IR: There are no really significant absorptions. So we can rule out C=O, -OH, NH, etc. (Anyway they are precluded based on the formula). Maybe the only peak to identify is the C=C at @ 1600cm-1

13C nmr: The proton decoupled spectrum shows only 3 aliphatic C peaks (30-35ppm) and 4 sp2 C peaks (125-140ppm), indicating a total of 7 types of C. Since we know the formula, we know there must be some symmetry. The peaks at 125-140ppm should suggest a benzene system

1H nmr: First of all we only have 4 types of H showing up. After this, it's a good idea to tabluate the information to make sure you get it all correctly matched up:
 

d/ppm
multiplicity
integration
Inference
7.2
multiplet
5
 5 Ar-H, so a monosubstituted benzene
3.3
triplet
2
 deshieded CH2 coupled to a CH2
2.7
triplet
2
 deshieded CH2 coupled to a CH2
2.1
quintet
2
 slightly deshieded CH2 coupled to two CH2 (given the above)

The simplest information we get from the H nmr here is from the integrals (total of 11H) which, when compared to the formula, tells us we have all the H accounted for. The most obvious structural information in the H nmr data is that we have a phenyl group ( = monosubstituted benzene) C6H5 . By working with the coupled units we should determine that we must have a -CH2-CH2-CH2- unit

So with all this information we have the following 3 pieces: C6H5 -, -CH2-CH2-CH2- and -Br.

This means we only have one "middle" piece and two end pieces, which means we must have....

3-bromo-1-phenylpropane

The final step should always be to check what you have drawn. The easiest thing to check is usually the coupling patterns you would expect to see, and the chemical shifts of each unit.
You should be asking yourself : "Does my answer give me what the H-nmr shows ?"