WorksheetsChemical Shift
Total questions: 20
Worksheet time: 28mins
Which of the following deuterated solvents is able to show anisotropic shift over the protons of a given molecule?
CDCl3
C6D6
D2O
Deuterated methylene chloride
The chemical shift of an active NMR nucleus depends on the following properties:
Only inductive effects
Only mesomeric effects
Only anisotropic effects
All the mentioned effects
The chemical shift of an active NMR nucleous is higher...
When using a 300 MHz instrument
When using a 500 MHz instrument
When using a 100 MHz instrument
Chemical shift does not depend on the magnetic field of the instrument
When running a 1HNMR experiment, the most used reference is...
Water
Tetramethylsilane
Trimethylsilane
Chlorotrimethylsilane
In a 1HNMR spectrum, a peak with a chemical shift of 10 ppm is said to be...
Deshielded
All the two proposed answers
At Downfield
Non of the two proposed answers
In a 1HNMR spectrum, a peak at low frequency is said to be...
Deshielded
All the two proposed answers
Shielded
Non of the two proposed answers
The chemical shift (300 MHz, CDCl3) of the 1Hs of MeCl is lower (3.05 ppm) than for methylene chloride (5.30 ppm) due to anisotropic effects
False
True
The chemical shift (300 MHz, CDCl3) of the 1Hs of benzene is 7.26 ppm. This is only due to the inductive effect of the sp2 C hybridization of the ring.
False
True
Ortho 1Hs of anisole (300 MHz, CDCl3) are more shielded (6.30 ppm) than meta ones (7.26 ppm) mainly due to...
Anisotropic effects
Resonance effects
The use of CDCl3 as solvent
Inductive effects
The chemical shift of the ortho 1Hs of aniline (300 MHz, CDCl3) appear at lower frequencies than those in anisole.
True
False
In toluene, all the protons suffer resonance at the same frequency
False
True
How many different triplets does ethyl acetate show in its 1HNMR spectrum (300 MHz, CDCl3)?
2
1
0
4
How many different singlets does methyl acetate show in its 1HNMR spectrum (300 MHz, CDCl3)?
2
1
0
3
How many different triplets does 1,2-ethanediol show in its 1HNMR spectrum (300 MHz, CDCl3)?
2
1
0
3
The reduction of 2-pentyne yields a compound which shows, among others, two NMR absorptions around 6 ppm in the 1HNMR spectrum (300 MHz, CDCl3). Which reagent has been used to reduce 2-pentyne?
H2O2
Lindlar's catalyst
H2, Pd/C
NaBH4
The reduction of 2-pentyne yields a compound which shows only aliphatic peaks below 2 ppm in the 1HNMR spectrum (300 MHz, CDCl3). Which reagent has been used to reduce 2-pentyne?
PtO2
Lindlar's catalyst
H2, Pd/C
Na/NH3
The reaction of 1-chloropropane with a methanolic solution of sodium methoxide (NaOMe) yields, as a major product, a compound which does not show relevant absorptions over 5.5 ppm in the 1HNMR spectrum (300 MHz, CDCl3). What process has taken place when running this reaction?
Unimolecular elimination (E1)
Biimolecular elimination (E2)
Unimolecular nucleophilic substitution (SN1)
Bimolecular nucleophilic substitution (SN2)
How many residual peaks does show CDCl3 (99.9% D)?
1
2
0
3
How many residual peaks does show CD2Cl2 (99.9% D)?
1
0
2
3
How many residual peaks does show pyridine-d5 (99.9% D)?
1
0
2
3
