Question

In an 1H NMR spectrum using CDCl3, you observe a broad peak at 1.5ppm that is...

In an 1H NMR spectrum using CDCl3, you observe a broad peak at 1.5ppm that is not related to your product and integrates for 2.6 Hs relative to a methyl group. What could be responsible for this peak and what might this indicate about your sample?

Science   Chemistry   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

The broad peak obtained at 1.5 ppm in 1H NMR spectrum using CDCl3 is due to the water present in the NMR tube. The source of this water can be moisture present in the sample or moisture present in the CDCl3 solvent.

The amount of moisture is variable; therefore integration of this peak at 1.5 ppm is not fixed. Integration increases with increase in water concentration and decreases with decrease in water concentration in NMR sample.

In the given sample if increasing the sample concentration increases the integration of moisture peak, then it can be concluded that sample contains water. However, if the integration remains same (2.6H) even after increasing sample concentration, then it can be concluded that the source of water is NMR solvent (CDCl3).

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Predict what changes, if any, would you expect in the 1H NMR spectrum if trimethylazulene in...
Predict what changes, if any, would you expect in the 1H NMR spectrum if trimethylazulene in CDCl3 were treated with D2O and a small amount of D2SO4. Any changes in the 13C NMR? What changes, if any, would you expect in the 1H NMR spectrum if trimethylazulene were treated with D2O and a small amount of KOtBu? Any changes in the 13C NMR?
A compound, C9H12, shows an IR peak at 750 cm-1. Its 1H NMR spectrum has peaks...
A compound, C9H12, shows an IR peak at 750 cm-1. Its 1H NMR spectrum has peaks at delta 7.1 (4 H, broad singlet), 2.6 (2 H, quartet, J=8 Hz), 2.3 (3 H, singlet), and 1.2 (3 H, triplet, J=8 Hz). Draw its structure in the window below.
A compound, C10H14, shows an IR peak at 745 cm-1. Its 1H NMR spectrum has peaks...
A compound, C10H14, shows an IR peak at 745 cm-1. Its 1H NMR spectrum has peaks at delta 7.18 (4 H, broad singlet), 2.70 (4 H, quartet, J=7 Hz), and 1.20 (6 H, triplet, J=7 Hz). Draw its structure in the window below. You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. In cases where there is more than one answer, just draw one.
onstruct a simulated 1H NMR spectrum, including proton integrations, for CH3CH2CO2CH2CH3. Drag the appropriate splitting patterns...
onstruct a simulated 1H NMR spectrum, including proton integrations, for CH3CH2CO2CH2CH3. Drag the appropriate splitting patterns to the approximate chemical shift positions. Drag the integration values in the small bins above the associated chemical shift. Splitting patterns and integrations may be used more than once, or not at all. Some bins might remain blank. Note that peak heights are arbitrary and do not indicate proton integrations. Note: Within a particular chemical shift zone, how do CH3 vs CH2 vs CH...
Scrutinize the 13C NMR spectrum of the methyl 3-nitrobenzoate If you had not kept watch over...
Scrutinize the 13C NMR spectrum of the methyl 3-nitrobenzoate If you had not kept watch over the reaction temperature, how might this affect the 13C NMR of the product isolated from this reaction? (Hint: what product is likely to be obtained at higher reaction temperature?)
There may be a peak or peaks in your spectrum for which you are unable to...
There may be a peak or peaks in your spectrum for which you are unable to assign a transition in the Balmer series. What might such an unknown peak be due to?
(3 pts) In the mass spectrum on page 3, what name do we give the peak...
(3 pts) In the mass spectrum on page 3, what name do we give the peak at 150 m/z units? (1) base peak     (2) molecular ion     (3) molecular fragment       (4) baseline (3 pts) In the mass spectrum on page 3, what name do we give the peak at 135 m/z units? (1) base peak     (2) molecular ion     (3) molecular fragment       (4) baseline (3 pts) The absorbances present in an IR spectrum result from: (1) “spin flipping” of nuclei     (2) fragmentation...
** synthesis of p-nitroaniline Based on the melting point of the recrystallized product, can you verify...
** synthesis of p-nitroaniline Based on the melting point of the recrystallized product, can you verify that the major product of the reaction was indeed p-nitroacetanilide? If you were to perform a TLC analysis of your crude product, how would you know if some of your product had undergone hydrolysis? (Hint: How many spots might you see, and what might their Rf values indicate regarding their polarities? Refer to your answer to Pre-Lab Q 4b) In which region of the...
2. You have carried out a synthesis reaction and isolated the solid crude product. Scrutiny of...
2. You have carried out a synthesis reaction and isolated the solid crude product. Scrutiny of its 1H NMR spectrum indicates the presence of an impurity, which you estimate to be approximately 6-8% of the total sample. You decide to purify it via recrystallization and know that you will first need to determine which solvent or solvent pair would be suitable. Describe what you would do and how you would evaluate your results. What properties of the solvent would you...
Alkene Hydration LAB 3.    Choose the starting materials: styrene, and water, which is the solvent. 4.    Return to...
Alkene Hydration LAB 3.    Choose the starting materials: styrene, and water, which is the solvent. 4.    Return to the lab and build the experiment apparatus, which includes a heater, condenser, nitrogen gas. 5.    Add the reagent, sulfuric acid (H2SO4) to the reaction flask. 6.    You will monitor the reaction progress using the pull down TV and TLC. QUESTION 1 The product produce when styrene is reacted with sulfuric acid in the presence of water is a. benzoic acid b. phenol c. 1-phenylethanol d. 2-phenolethanol...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT