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-4. Predict the structure of an unknown compound from the following Mass Spectro

ID: 1087112 • Letter: #

Question

-4. Predict the structure of an unknown compound from the following Mass Spectroscopy data: (5 pts) M' = m/2 102, relative abundance 50% (M +1)·m/s 103, relative abundance 3.3% B. CH0 D. CHs F. C,HsO G. -5. Please select the peak(s) from infrared spectroscopy that will be lost and gained during the following transformation. (more than one apply) (5 pts) NaBH,, MeOH OH A. Loss of broad peak between 3200-3600 cm B. Gain of peak between 2100-2200 cm C. Loss of peak between 500-600 cm D. Gain of peak between 3200-3600 cm E. Gain of peak between 1600-1700 cm F. Gain of peak between 1680-1750 cm G. Gain of peak between 500-600 cm H. Gain of peak at 3300 cm I. Loss of peak between 1680-1750 cm

Explanation / Answer

1 we have formula

number of carbons = ( 100/1.1) ( M+1 peak / M peak)

= ( 100/1.1) ( 3.3 /50) = 6

Thus we had 6C which has mass of 6 x 12 = 72 g/mol

remaining mass of 102-72 = 30g/mol are due to 1O and 14 H ,

hence formula is C6H14O

2) C=O peak corresponds to 1680cm-1 to 1750 cm-1 and C-OH has peak near 3300cm-1

Hence we lose peak between 1680-1750 cm-1 and gain peak at 3300 cm-1

Hence H and I are options