Question

100- 1 24 67 17 18 50 4000 3000 2000 Wavenumber [cm-1) 1000 Accumulation Resolution Apodation Scanning Speed Auto (16) 10/28/2019 3.08PM Parris Kapple Memory 4cm-1 Cosine Auto (2 mm/sec) 10/28/2019 3 09PM Update Sample Name Comment No cm.1 91 801 91 9911 91.9663 91 8702 Nem-1 1396875 63843.43 110266 16 9630 34 21 2953.45 201702 84 31 1455.03 36 1285.32 41 972 912 46 744388 51 587.218 56 482 117 92.5818 80.3571 19 8173 51.3565 74.0059 81.5858 No om-1 2391861 7 360197 12 3691.09 17 3567.66 22 2921.63 27 1654.62 32 142.96 37 1237.11 42 926 628 47 698. 105 52 566.969 57 462 832 %T 91.9159 926579 93 1806 91 2521 81.8838 17.9931 54.4609 54.3453 111.232 Noem-1 33905. 15 8 3751.83 13 3576.62 18 3475.1 23 2850.27 28 1598.7 33 1401.03 38 1186 97 43 862.025 40 000 214 53 566 363 58 446 44 91 8178 92 3205 93 2476 0.188 914298 52 6496 71.3902 80.3963 105.107 124.404 132 359 106,603 14 30583 193112 55 24 2361.41 29 1548.56 34 1357.64 39106741 44 800 314 49 644.108 54 526.471 59 427.155 83 530 96.1486 45.4413 63.8424 106.023 121.239 122.969 134 315 82.9067 Noom-1 5 3856.01 10 3724,83 153649.62 20 3010.34 25 2343 09 30 1406 85 35 1325 62 40 1024.90 45 758.852 59 611.324 55492.723 60 470.406 91 5920 83 0206 93 5391 94 2138 100 355 47.9688 89.7928 77 6151 81 0935 63.5159 127 431 128.156 75.7457 131.255 123.998
What are the key functional groups and their frequencies in the IR spectrum of caffeine. Is it pure?

Answer 1

Major peaks in Caffeine:

Sl .No	Peak position (cm-1)	Assignment
1	2953	C-H stretch in –CH3
2	1699	C=O stretch in amide
3	1655	N-H bend
4	1486	C-N stretch
3	744	Ourt of plane C_H bend

The compound appears reasonably pure. IR spectra matches quite well with known spectra of Caffeine.