Organic Chemistry II
	Professor Carl C. Wamser
Chem 335 - Winter 2007	Quiz 13

1. (3 points) For the formula C2H4O , what is the index of hydrogen deficiency and what does it mean for a compound with this formula?

IHD = 1 , indicating there is one ring or double bond

There are only three possible compounds with this formula. Indicate how you would use infrared spectroscopy to distinguish among each of the three isomers.

2. (3 points) The C-13 NMR spectrum of p-xylene (1,4-dimethylbenzene) shows only three absorptions. Describe the three absorptions in terms of the expected range (in ppm), the multiplicity of each absorption in a H-coupled spectrum, and indicate which carbons in the structure give rise to each of the absorptions.

Absorption / / / Range / / / H-coupling multiplicity / / / Structure

3. (4 points) An unknown compound of formula C10H13Br gives the following H-1 NMR spectrum. Identify the compound and indicate which hydrogens give rise to each absorption (label them a, b, c, d).

a 7.5 ppm, 5 H , multiplet
b 1.7 ppm, 2 H , quartet
c 1.5 ppm, 3 H , singlet
d 1.0 ppm, 3 H , triplet

What would you calculate for the (m/z) values and the relative intensities of the parent molecular ions for this compound?

M = (120 + 13 + 79) = 212 , (M+2) = (120 + 13 + 81) = 214

M and M+2 in approximately equal intensities (51:49)