Final, IR and NMR

Question 1

Give a frequency and description of the IR spectrum of C-C

Answer 1

Around 1000 (not really used)

Question 2

Give a frequency and description of the IR spectrum of C=C

Answer 2

Around 1660

Small-medium intensity

Question 3

Give a frequency and description of the IR spectrum of C≡C

Answer 3

Around 2150

Small-Medium Intensity with sharp peaks

Question 4

Give a frequency and description of the IR spectrum of C-H (sp3)

Answer 4

Less than 3000

Question 5

Give a frequency and description of the IR spectrum of C-H (sp2)

Answer 5

Greater than 3000

Question 6

Give a frequency and description of the IR spectrum of C-H (sp)

Answer 6

Greater than 3000

Question 7

Give a frequency and description of the IR spectrum of C=O

Answer 7

Around 1700

Very high intensity, dominating the spectrum

Question 8

Give a frequency and description of the IR spectrum of C-O

Answer 8

Around 1200

Less than C=O due to single bond

Question 9

Give a frequency and description of the IR spectrum of O-H

Answer 9

Huge range from 3500-3600

Dilute will be higher, very broad peak

Question 10

Give a frequency and description of the IR spectrum of N-H

Answer 10

Range from 3500-3300

N has less EN-> smaller wavenumbers

Question 11

Give a frequency and description of the IR spectrum of C≡N

Answer 11

Around 2250

Small-Medium Intensity Peaks that are relatively sharp

Question 12

How many peaks will Primary, Secondary, and Tertiary Amines have in the N-H range?

Answer 12

two, one, or zero

Question 13

What vibrational frequency is around 2250 and has peaks that are small-medium intensity that are relatively sharp?

Answer 13

C≡N

Question 14

What vibrational frequency is around 1200?

Answer 14

C-O

Question 15

What vibrational frequency is around 3000+?

Answer 15

C-H sp2 and sp

Question 16

What vibrational frequency is around 2150 with small-medium intensity sharp peaks?

Answer 16

C≡C

Question 17

What vibrational frequency is around 1700 and has very high intensity peaks dominating the spectrum?

Answer 17

C=O

Question 18

What vibrational frequency is around 3000-?

Answer 18

C-H sp3

Question 19

What vibrational frequency is around 3500-3600 and has a very broad peak?

Answer 19

O-H

Question 20

What vibrational frequency is around 1660 and has small-medium intensity peaks?

Answer 20

C=C

Question 21

What does the number of signals in an NMR spectrum tell you?

Answer 21

how many different protons or carbons you have

Question 22

What does the position of signals in an NMR spectrum tell you?

Answer 22

The position of the signals tells you their environment (electron density)

Lower chemical shift values are called more ‘upfield’ and are shielded by electrons
Higher chemical shift values are called more “downfield” and are deshielded by close proximity to an electronegative group such as a halogen

Question 23

What does the area under a signal in an NMR spectrum tell you?

Answer 23

number of protons/carbons per signal

Question 24

What does the multiplicity of a signal in an NMR tell you?

Answer 24

the number of protons or carbons less than three bonds away from the one being measured
N neighbors of magnetically equivalent protons/carbons + 1

Four and Three is a CH2CH3

Question 25

What is the typical HMNR chemical shift for 1* to 3* Alkyl? (Small scale)

Answer 25

1 to 2

Question 26

What is the typical HMNR chemical shift for ketones? (Small scale)

Answer 26

2-2.5

Question 27

What is the typical HMNR chemical shift for aromatic groups? (Small scale)

Answer 27

7ish

Question 28

What is the typical HMNR chemical shift for aldehydes? (Small scale)

Answer 28

around 10

Question 29

What is the typical HMNR chemical shift for carboxylic groups? (Small scale)

Answer 29

10-13

Question 30

What is the typical CMNR chemical shift for aldehydes and ketones? (Large scale)

Answer 30

180-215

Question 31

What is the typical CMNR chemical shift for esters and carboxylic acids? (Large scale)

Answer 31

160-185

Question 32

What is the typical CMNR chemical shift for Aryl Carbons? (Large scale)

Answer 32

100-170

Question 33

What is the typical CMNR chemical shift for 1* to 3* Alkyls? (Large scale)

Answer 33

0-50