Question

3) Match the IR spectra that follow with compounds A-F (From question 1). result 4000 3000 2000 1500 Wavenumber [cm] 1000 400

please just answer the 2 boxes in the first picture and the last box in the second pic. A-F structures are in the 3rd pic.

thank you and please write neatly

Answer 1

1) 3090: sp2 C-H stretching 2966 and 2895: sp3 C-H stretchin 1745: ester CEO stretching 1610: aromatic C=C stretching 1460: CH2 scissoring 1350: sp3 C-H bending 1230: C-O stretching ester 751: OOP C-H bending 698: ring bending these last two peaks indicate monosubstituted ring. All these functional groups are present in option-A. Thus the first spectrum is of benzyl acetate and answer is option-A. Let's rule out the options: the carbonyl stretching is not lowerd as it is expected in option-B due to conjugation. Hence rule out option B. Option C and F are ruled out because they do not have C=O. Option D contains aldehyde and hence expected to have C-H peak at 2750. And Option E is carboxylic acid so broad peak is expected above 3000. So we can rule out option D and E.

2) 2960 and 2830: sp3 C-H stretching 1620: weak peak C=C stretching 1460: CH2 scissoring 1350: sp3 C-H bending No carobonyl stretching hence rule out A, B, D and F. No peak above 3000 wrt-OH hence rule out option C and E. Thus the compound is F. H2CCH Limonene

3) Broad peak 2400-3600:-COOH 1720: C=O stretching 1450: CH2 Scissoring 1350: sp3 C-H bending There is only one compound with COOH functional group hence answer is propanoic acid: Option-E.