1. Which one of the following shows the ¹³C NMR spectrum of
pentan-3-one, C₅H₁₀O?

Solution

2. A sample separated from a mixture of compounds produced the IR spectrum shown below.

State whether this spectrum was produced by an amine or a carboxylic acid.
( 1 mark)

Solution

3. Compound X, known to contain both oxygen and chlorine, was purified from a waste sample to enable it to be re-used.

a. The mass spectrum of Compound X is shown below:
• The only stable isotope of oxygen is ¹⁶O.
• The two naturally occurring, stable isotopes of chlorine are ³⁵Cl and ³⁷Cl.

i. Identify the m/z of the base peak. (1 mark)

ii. State why all the possible isomers of Compound X would have the same peak at m/z = 108. (1 mark)

iii. Identify the formula of the species responsible for the peak at m/z = 95.
(1 mark)

Solution.

b. The high-resolution ¹H NMR spectrum for Compound X is shown below.

Data obtained from the ¹H NMR spectrum for Compound X is shown in the table below.

Referring to the ¹H NMR spectrum and the table above, deduce three things about the structure of Compound X. (3 marks)

Solution

c. The ¹³C NMR spectrum for Compound X is shown below.

What does the ¹³C NMR spectrum indicate about the structure of Compound X? (2 marks)

Solution

d. i. In the space provided below, draw the skeletal diagram of Compound X that is consistent with the information provided in parts c–e. (1 mark)

ii. Write the IUPAC name of Compound X. (1 mark)

Solution