Problem 1
Give a brief account of how an EI mass spectrometer functions.
Problem 3
A compound \(\mathbf{Y}\) contains \(58.77 \%\) C and \(27.42 \%\) N. From an exact mass determination, the molecular weight of \(\mathbf{Y}\) is found to be \(102.11576 .\) Suggest a likely composition for \(\mathbf{Y}\).
Problem 6
Suggest what peaks might be present in the mass spectra of (a) \(\mathrm{F}_{2}\) and (b) \(\mathrm{Cl}_{2}\)
Problem 9
In its mass spectrum, a compound A shows a peak from the molecular ion at \(m / z=78 .\) What further information from the parent ion allows you to distinguish between A being \(\mathrm{C}_{6} \mathrm{H}_{6}\) and \(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{Cl} ?\)
Problem 10
The mass spectrum of a compound B contains major peaks at \(m / z=74,59,45,31,29\) and \(27,\) and a lower intensity peak at \(m / z=15 .\) B is known to be either butanol (10.6) or diethyl ether (10.7). Do the mass spectrometric data allow you to unambiguously assign \(\mathbf{B}\) as butanol or diethyl ether?
Problem 11
The compounds \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{SH}\) and \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}\) both show parent ions in their mass spectra at \(m / z=62 .\) How do the fragmentation patterns allow you to distinguish between the two compounds?
Problem 14
Compound \(\mathbf{D}\) contains \(68.13 \% \mathrm{C}, 13.72 \% \mathrm{H}\) \(18.15 \%\) O, and shows a parent ion in its mass spectrum at \(m / z=88 .\) Determine the molecular formula of \(\mathbf{D}\).
Problem 15
Compound \(\mathbf{E}\) exhibits a parent ion in its mass spectrum at \(m / z=92,\) and analysis of \(\mathbf{E}\) gives \(91.25 \% \mathrm{C}\) and \(8.75 \%\) H. Determine the molecular formula of \(\mathbf{E}\).
Problem 16
The mass spectrum of compound \(\mathbf{F}\) contains a base peak at \(m / z=91,\) and a parent ion at 106 (relative intensity 37.5 ). \(\mathbf{F}\) is known to be a derivative of benzene with structure 10.10 in which \(R\) is an unknown group. Identify \(\mathbf{F}\) and rationalize the mass spectrometric data.
Problem 19
Naturally occurring Fe consists of \(5.8 \%^{54} \mathrm{Fe}\) \(91.7 \%^{56} \mathrm{Fe}, 2.2 \%^{57} \mathrm{Fe}\) and \(0.3 \%^{58} \mathrm{Fe} . \mathrm{Fe}(\mathrm{CO})\) (10.12) loses \(\mathrm{CO}\) molecules in a sequential manner in the mass spectrometer. What do you expect to observe in the mass spectrum of \(\mathrm{Fe}(\mathrm{CO})_{5} ?\)
