MSpract2

Based on DBE, Which formula is unlikely to have molecular ion at m/z = 86?

• C₆H₁₄

• C₅H₁₀O

• C₄H₈NO

• C₄H₆O₂

Based on the nitrogen rule, which formula is likely to give a molecular ion at m/z = 86?

• C₃H₈N₃

• C₄H₁₀N₂

• CH₄N₅

• C₅H₁₂N

Based on the rule of 13, which is not a possible formula of molecular ion at m/z = 56?

• C₄H₆

• C₄H₈

• C₃H₄O

• C₂H₄N₂

Match the structure to this mass spectrum

• A

• B

• C

Match the structure to this mass spectrum

• A

• B

• C

What ion gives rise to the peak at m/z = 43 in the mass spectrum of acetone (CH₃C=OCH₃ MW 58)?

• CH₃⁺

• CH₃CH₂⁺

• CH₃CO⁺

• CHO⁺

Which compound is likely to give fragment ion (M-28) via McLafferty rearrangement

• acetone

• 2-pentanone

• 3-pentanone

• acetophenone

Mass spectrum of ethyl benzene (Mw 106) shows base peak at m/z 91, what is this ion?

• benzyl radical

• ethyl ion

• phenyl ion

• tropylium ion

Which ions are responsible for the peaks at m/z 43, and 57 in the mass spectrum of 2,2-dimethylbutane?

• ethyl and t-butyl cations

• ethyl and sec-butyl cations

• ethyl and propyl cations

• propyl and t-butyl cations

The MS spectrum of compound A shows the relative heights (abundances) of the M+ and M+1 peaks in the ratio of 25:2, how many carbon in this compound?

• 6

• 7

• 8

• 9