Chapter 1 Practice Problems

Answers for these practice problems are in the next section.

A good approach is to answer all of the questions on a piece of paper and then check your answers. This avoids accidentally seeing the answer(s) for questions you have not done yet.

Q1.1: How many signals appear in the ¹H NMR spectrum of the following compound?

a. 5

b. 6

c. 7

d. 10

Q1.2: How many signals appear in the ¹³C NMR spectrum of the following compound?

a. 9

b. 10

c. 11

d. 14

Q1.3: The signal for which of these hydrogen atoms would be the furthest upfield (have the lowest chemical shift/ppm) in the compound’s ¹H NMR spectrum?

Q1.4: How many triplets appear in the ¹H NMR spectrum of the following molecule?

a. 1

b. 2

c. 3

d. 4

Q1.5: Which of the following compounds has the most signals in its ¹³C NMR spectrum?

Q1.6: Which of the following compounds has a ¹H NMR spectrum with 2 quartets and 2 triplets?

Q1.7: Analysis of a pure sample labelled “nitrotoluene” shows a ¹H NMR spectrum with the following signals:

• a doublet at 7.9 ppm (integrating to 2H)

• a doublet at 7.1 ppm (integrating to 2H)

• a singlet at 2.3 ppm (integrating to 3H)

Based on this, the sample is made of which isomer of nitrotoluene?

a.

b.

c.

d. None of the above.

Q1.8: Consider the following ¹H NMR spectrum with 3 signals:

Which of the following compounds could produce that ¹H NMR spectrum?

Q1.9: For each of the indicated chemically distinct sets of hydrogen atoms predict the multiplicity (shape, coupling pattern) of the signals present in the compound’s ¹H NMR spectrum (e.g. singlet, doublet, triplet, quartet, doublet of triplets, triplet of quartets, etc.).

The multiplicity for the signal for the hydrogen atoms labelled (a) would be

__________________________________________________________________.

The multiplicity for the signal for the hydrogen atom labelled (b) would be

__________________________________________________________________.

The multiplicity for the signal for the hydrogen atoms labelled (c) would be

__________________________________________________________________.

The multiplicity for the signal for the hydrogen atom labelled (d) would be

__________________________________________________________________.

The multiplicity for the signal for the hydrogen atom labelled (e) would be

__________________________________________________________________.

In place of a set of dedicated structure-solving practice problems students are encouraged to visit the following resource:

¹H NMR Practice Problem Database (opens a new tab)

This site contains many practice problems that test your ability to draw a structure from a spectrum (Section 1.12) which gives practice with most of the skills from this chapter.

• Open the link (NOTE: this website works best on a tablet, laptop, or desktop computer, not on a phone)
• Click an exercise number on the far left. A molecular formula with a spectrum will appear. Beneath the spectrum is a large amount of useful data including chemical shifts, integrations, and multiplicities. There are 16 practice problems automatically generated when you open the page (scroll down while having the cursor over the red box on the left to show more problems).
• Solve the structure using the data provided and draw your molecule in the toolbox provided. Correct answers will automatically be highlighted in green once entered.
  • o If you find drawing the structure in the toolbox too difficult instead draw it on a piece of paper nearby. Then, once you have done as many as you would like click the “show answers” button and double check your work.