Kaplan Organic Chemistry: Chapter 10 Spectroscopy

Question 1

In IR, where would you find a:

1) carbonyl peak
2) OH group
3) NH peak
4) aromatic
5) carboxylic aid
6) C=C

Answer 1

1) carbonyl peak: 1700cm-1
2) OH group: 3300cm-1 BROAD
3) NH peak: 3300cm-1 SHARP
4) aromatic: 2900-3100CH, 1475-1635 C-C
5) carboxylic aid: two peaks corresponding to OH and C=O
6) C=C: 1580-1640

Question 2

How does IR spec work

Answer 2

absorption of IR light results in VIBRATION of atoms in polar bonds

Question 3

how does UV spec work

Answer 3

absorption of UV light results in excitation of BOUND e-,

Question 4

UV spec works best for conjugated systems that have _____ ____ orbitals which can be excited by ultraviolet light

Answer 4

conjugated systems that have UNHYBRIDIZED P ORBITALS.

Question 5

in proton NMR, deshielded protons will be ____

Answer 5

left. ex/ atoms near an electronegative atom pulling away negative harge and allowing the proton to have less interactions and be more free.

Question 6

number of peaks equation in H NMR

Answer 6

n+1 n= number of neighbors.

Question 7

Where would you see shifts in a proton NMR Of:

1) deshielded aldehyde
2) carboxylic acid
3) aromatic rings
4) alkenes
5) alkynes
6) alkyl

Answer 7

1) deshielded aldehyde: 9-10ppm
2) carboxylic acid: 10-12ppm
3) aromatic rings: 6-8.5 ppm
4) alkenes: 4-6 ppm
5) alkynes 2-3ppm
6) alkyl: 0-3ppm