Spec Problems
Extra Problems
8. A common, organic solvent gives a mass spectrum that shows an M+ peak at 41. The IR spectrum for this solvent shows peaks at about 2950 and 2254 cm-1.
a) Propose a viable molecular formula for this solvent. Viable means it corresponds to at least one stable, neutral compound.
b) Propose a structure that is consistent with all of the spectroscopic information given above.
9. Based on their molecular formula, determine the number of elements of unsaturation in the following compounds.
a) C7H10N2O
b) C6H10O
c) C7H11OCl
d) C6H7N
e) C5H5N
f) C10H18
g) C5H11Br
10. For the following MS molecular ion isotope patterns, describe which heteroatom is indicated.
11. Two bottles were found that contained fingernail polish remover. One bottle was acetone and the other was non-acetone remover (ethyl acetate). The bottle labels were removed, so you wanted to identify which bottle contained which compound. IR spectra were obtained to identify them. Spectrum A is acetone and spectrum B is ethyl acetate. Clearly identify which IR spectrum goes with which compound structure.
12. Your summer job is to clean up an organic chemistry laboratory. You must identify some bottles with illegible labels. In each problem below, describe one difference that you would expect to see in the IR spectra of the two compounds that will allow you to identify which compound it is.
13. For the following reactions, indicate the changes you would see in the IR spectra between then reactant and the product.
14. The following IR spectrum was taken of a compound. A student identified the compound as an aldehyde because of the two peaks marked. a) Why was this student incorrect? What major peak is missing from this IR spectrum if it is indeed an aldehyde?
b) After realizing those were not aldehyde peaks, but sp3 C-H peaks, the student noticed that this compound had, in its mass spectrum, an M+ peak at 73. Then, the student noticed the following, previously overlooked peak in the IR spectrum. This was indeed a significant peak. What type of compound might this student have?
