IR Absorption of Functional Groups

Question 1

Alcohol (O-H)

Answer 1

3200-3600 strong, broad

Question 2

Alkane (C-H)

Answer 2

2850-3000 strong

Question 3

Terminal Alkene (=C-H)

Answer 3

3010-3100 medium

Question 4

Alkene (C=C)

Answer 4

1620-1680 variable

Question 5

Terminal Alkyne (≡C-H)

Answer 5

3300 strong and sharp

Question 6

Amine (N-H)

Answer 6

3300-3500 medium (1° - two bands; 2° - one band)

Question 7

Aromatic (C-H)

Answer 7

3000-3100 medium

Question 8

Aromatic (C=C)

Answer 8

1400-1600 medium-weak, multiple bands

Question 9

Ether (C-O)

Answer 9

1000-1300 (1070-1150) strong

Question 10

Nitrile (C≡N)

Answer 10

2210-2260 medium

Question 11

Nitro (N=O)

Answer 11

1515-1560 strong

Question 12

Nitro (N-O)

Answer 12

1345-1385 Strong

Question 13

Carboxylic Acid

Answer 13

C=O 1700-1725 strong + O-H 2500-3300 strong, very broad + C-O 1210-1320 strong

Question 14

Aldehyde

Answer 14

C=O 1740-1720 strong + C-H 2820-2850 & 2720-2750 medium, two peaks

Question 15

Aminde

Answer 15

C=O 1640-1690 strong + N-H 3100-3500 unsubstituted have two bands

Question 16

Anhydride

Answer 16

C=O 1800-1830 & 1740-1775 strong (two bands) + C-O 1210-1320 strong

Question 17

Ester

Answer 17

C=O 1735-1750 strong + C-O 1000-1300 strong (two bands or more)

Question 18

Ketone C=O

Answer 18

1680-1850 strong