Question

Question:Identify each of the following compounds from its mass spectrum, IR spectrum, ¹H and NMR spectrum:

a.

b.

Short answer

a.

b.

Step-by-step solution

IR spectroscopy

It stands for infrared spectroscopy which is used to identify the functional groups in the compound as each and every functional group shows absorption at different wavenumber which differentiatesthe compounds.

Identify compound A

The absorption is between 1730 cm^-1shows the presence of an aldehyde but the absence of the stretching of the C-H in the aldehyde shows the presence of the ketone and the mass spectra show the mass to charge ratio at 114 which also shows the presence of ketone and symmetrical ketone is present due to the NMR peak which is only show due to them CH₃CH₂COand the large fragment is produced at 77 due to the propyl and at 43 due to the propyl cation hence, only three signal are produce shows symmetrical ketone as given below:

Compound A

Identify compound B

As per the given data the M+2 peak is given at m/z = 156 shows the presence of chlorine.

IR spectra show it is acetone.

NMR spectra show it is a monosubstituted benzene ring and the peak at 4.7 ppm indicates the methylene group giving a strong signal due to the electron-withdrawing environment and the major fragment at m/z=105 M-CH₂Cl and m/z=77 due to C₆H₅⁺ as shown by the given structure:

Compound B