Organic Spectroscopy (O1)

Question 1

What is the Index of Hydrogen Deficiency (IHD) equation?

Answer 1

IHD = (2 C + 2 – H – X + N) / 2

Question 2

Maximum peak of mass spectrum of molecule containing Br or Cl?

Answer 2

M+2

Question 3

Approximate IR band of O-H?

Answer 3

3600 cm^-1 (if hydrogen bonding, 3400 - 2800 cm^-1 broad)

Question 4

Approximate IR band of N-H?

Answer 4

3500 - 3300 cm^-1

Question 5

Approximate IR band of alkyne-H?

Answer 5

3300 cm^-1

Question 6

Approximate IR band of alkene-H?

Answer 6

3100 - 3000 cm^-1

Question 7

Approximate IR band of alkane-H?

Answer 7

3000 - 2850 cm^-1

Question 8

Approximate IR band of thiol H?

Answer 8

2600 - 2550 cm^-1

Question 9

Approximate IR band of carboxylic acid C=O?

Answer 9

1790 - 1740 cm^-1

Question 10

Approximate IR band of acid anhydride C=O?

Answer 10

1850 - 1800 cm^-1

Question 11

Approximate IR band of ester C=O?

Answer 11

1750 - 1735 cm^-1

Question 12

Approximate IR band of aldehyde C=O?

Answer 12

1740 - 1720 cm^-1

Question 13

Approximate IR band of ketone C=O?

Answer 13

1725 - 1705 cm^-1

Question 14

Approximate IR band of alpha, beta-unsaturated ketone C=O?

Answer 14

1685 - 1665 cm^-1

Question 15

Approximate IR band of ether C-O?

Answer 15

1150 - 1070 cm^-1

Question 16

Approximate IR band of alkyne C-C?

Answer 16

2260 - 2100 cm^-1

Question 17

Approximate IR band of nitrile C-N?

Answer 17

2260 - 2200 cm^-1

Question 18

Approximate IR band of alkene C=C?

Answer 18

1680 - 1620 cm^-1

Question 19

Approximate IR band of aromatic C=C?

Answer 19

1600, 1580, 1500 cm^-1 (+ overtone bands between 2000 - 1665 cm^-1)

Question 20

Approximate IR band of aromatic C=C?

Answer 20

1600, 1580, 1500 cm^-1 (+ overtone bands between 2000 - 1665 cm^-1)

Question 21

Approximate IR band of nitro N-O?

Answer 21

1560 and 1350 cm^-1

Question 22

Beer-Lambert Law

Answer 22

A = elC

Question 23

Beer-Lambert Law

Answer 23

A = elC

Question 24

Approximate alkane 1H NMR shift?

Answer 24

0.5 - 2.0 ppm

Question 25

Approximate alkene 1H NMR shift?

Answer 25

4.0 - 7.5 ppm

Question 26

Approximate alkyne 1H NMR shift?

Answer 26

1.8 - 3.1 ppm

Question 27

Approximate arene 1H NMR shift?

Answer 27

6.0 - 9.5 ppm

Question 28

Approximate aldehyde 1H NMR shift?

Answer 28

9.4 - 10.8 ppm (extremely deshielded)

Question 29

Approximate ester 1H NMR shift?

Answer 29

3.3 - 3.8 ppm (slight deshielding due to electronegative oxygen)

Question 30

Approximate geminal 1H NMR coupling constant?

Answer 30

0 - 3 Hz

Question 31

Approximate trans-vincinal 1H NMR coupling constant?

Answer 31

13.0 - 18.0 Hz (as describes by Karplus Equation)

Question 32

Approximate cis-vincinal 1H NMR coupling constant?

Answer 32

7.0 - 12.0 Hz (as describes by Karplus Equation)

Question 33

Approximate ortho 1H NMR coupling constant?

Answer 33

7.0 - 10.0 Hz

Question 34

Approximate meta 1H NMR coupling constant?

Answer 34

2.0 - 3.0 Hz

Question 35

Approximate para 1H NMR coupling constant?

Answer 35

0.1 - 1.0 Hz

Question 36

What does DEPT-135 show?

Answer 36

CH and CH3 groups point upwards, CH2 groups downwards, no quaternary

Question 37

What does DEPT-90 show?

Answer 37

Only CH groups

Question 38

What does DEPT-45 show?

Answer 38

All non-quaternary carbons

Question 39

What does a COSY spectrum show?

Answer 39

Through-bond H-H couplings

Question 40

What does a HMQC spectrum show?

Answer 40

Through-bond H-C couplings

Question 41

What does a NOESY spectrum show?

Answer 41

Through-space H-H couplings