Question

How would you distinguish between the following pairs by use of infrared Spectroscopy only? Tell what absorption would be present or absent in each case. A. 2-pentanone and 2-pentanol B. Acetophenone and p-tolualdehyde C. 3-pentanone and benzophenone How would you distinguish between the pairs a bowl of using only proton NMR spectroscopy? Sketch a possible spectrum for each

Answer 1

Distinguishing between organic compounds using IR

A. 2-pentanone and 2-pentanol

2-pentanone will have a peak in the 1700-1750 cm-1 region for C=O stretch which would be absent in 2-pentanol

2-pentanol will have a broad peak in the 3200-3600 cm-1 region due to O-H stretch. This peak is absent in 2-pentanone

B. Acetophenone and p-tolualdehyde

Acetophenone will have a peak in the region 1700-1740 cm-1 for C=O stretch. this is absent in p-tolualdehyde.

P-tolualdehyde will have two peaks in the region 2700-2840 cm-1 for H-C=O and C-H of aldehyde. This peak is absent in acetophenone.

C. 3-pentanone and benzophenone

3-pentanone will have no peaks above the region 3000 cm-1 and between 1500-1600 cm-1 region.

benzophenone will have peaks in the region 3000-3100 cm-1 for =C-H and 1500-1600 cm- region for C=C stretch.

pl. note : the other part of problem is not clear