please help! the second picture is benzoin acid the third and fourth pic is the
ID: 592711 • Letter: P
Question
please help!
the second picture is
benzoin acid
the third and fourth pic is the unknown
and the last pic is p-anisaldeyde
TECH0710: Identifying an Unknown Compound by Infrared Spectroscopy 165 nare section date Post-Laboratory Questions lv label the IR spectrum of benzoic acid with your name, laboratory section, the date, and "benzoic acid". Assign the following peaks: broad 3300-2500 cm- 3020 cm1 1682 cm1 (D) CIearlylabel the le pecnume ot maisl eaye wth your name, laboratory section, the date, and "p-anisaldehyde". Assign the following peaks: 3074, 3008 cm-1 2965 cm1 2834, 2736 cm-1 1695 cm-1Explanation / Answer
Spectral analysis,
1. (a) Benzoic acid
major peaks
3300-2500 cm-1 broad peak for O-H stretch of carboxylic acid
3020 cm-1 for sp2 =C-H stretch
1682 cm-1 for C=O stretch
1500-1600 cm-1 peaks for aromatic C=C stretch
(b) p-anisaldehyde
major peaks are,
3074 cm-1 for sp2 =C-H stretch
3008 cm-1 for sp2 =C-H stretch
2965 cm-1 for sp3 -C-H stretch
2834 cm-1 and 2736 cm-1 for aldehyde of anisaldehyde
1695 cm-1 for C=O stretch
1500-1600 cm-1 peaks for aromatic C=C stretch
Unknown
In both 3rd and the 4th spectrum,
the broad peak at 3300-2500 cm-1 is missing, so carboxylic acid group is not present
2850-2950 cm-1 peaks are for the sp3 -C-H stretch
1700 cm-1 peak for C=O stretch
Compound is most probably an aliphatic ketone like acetone.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.