Which technique is used to determine the bond lengths and bond angles of a molecule?

A.     X-ray crystallography

B.     Infrared (IR) spectroscopy

C.     Mass spectroscopy

D.     ¹H NMR spectroscopy

A

Which technique can be used to identify bond length and bond angle?

A.     ¹H NMR spectroscopy

B.     IR spectroscopy

C.     Mass spectroscopy

D.     X-ray crystallography

D

Which property explains why tetramethylsilane, Si(CH₃)₄, can be used as a reference standard in ¹H NMR spectroscopy?

A. It has a high boiling point.

B. It is a reactive compound.

C. All its protons are in the same chemical environment.

D. It gives multiple signals.

C

What information can be deduced from the splitting pattern of ¹H NMR signals?

A.  total number of hydrogen atoms in a compound

B.  number of hydrogen atoms on adjacent atom(s)

C.  functional group on which hydrogen atoms are located

D.  number of hydrogen atoms in a particular chemical environment

B

Which compound produces the following ¹H NMR spectrum?

SDBS, National Institute of Advanced Industrial Science and Technology (AIST).

A.  Propane

B.  Propanone

C.  Propanal

D.  2,2-dimethylpropane

A

Which technique may be used to find the bond lengths and bond angles within a molecule?

A.   X-ray crystallography

B.   ¹H NMR spectroscopy

C.   Infrared spectroscopy

D.   Mass spectroscopy

A

Which is the ¹H NMR spectrum of tetramethylsilane, TMS, (CH₃)₄Si?

C

Which can be identified using infrared (IR) spectroscopy?

A. functional groups

B. molar mass

C. 3-D configuration

D. bond angle

A

The vast majority of candidates knew that IR spectroscopy can be used to identify functional groups.

Which would be the most effective method to distinguish between liquid propan-1-ol and propan-2-ol?

A.     Observation of colour change when warmed with acidified potassium dichromate

B.     Determination of m/z value of molecular ion in the mass spectrum

C.     Determination of percentage composition

D.     ¹H NMR spectroscopy

D

Which compound gives this ¹H NMR spectrum?

A. CH₃CH₂OCH₂CH₃

B. CH₃CH₂OH

C. CH₃CH₂CH₃

D. CH₃CH₂CH₂OH

D

Which compound produces the following ¹H NMR spectrum?

^{[Spectral Database for Organic Compounds, SDBS. SDBS Compounds and Spectral Search. [graph] Available at:
https://sdbs.db.aist.go.jp [Accessed 3 January 2019].]}

A.  propanal

B.  propanone

C.  propane

D.  methlypropane

A

A majority of students identified the correct compound for the ¹H NMR spectrum given.

Which compound with the molecular formula ${\mathrm{C}}_4{\mathrm{H}}_8\mathrm{O}$ has this high resolution ${}_1\mathrm{H} \mathrm{NMR}$?

From: libretexts.org. Courtesy of Chris Schaller, Professor (Chemistry)
at College of Saint Benedict/Saint John’s University.

A.  but-3-en-2-ol, ${\mathrm{CH}}_2=\mathrm{CHCH}\left(\mathrm{OH}\right){\mathrm{CH}}_3$

B.  butanal, ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CHO}$

C.  butanone, ${\mathrm{CH}}_3{\mathrm{COCH}}_2{\mathrm{CH}}_3$

D.  but-3-en-1-ol, ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{CH}}_2\mathrm{OH}$

B

Just over 50% of candidates could identify the correct compound from high resolution 1H NMR data. The question had a relatively high discriminatory index.

Which substance has the following ¹H NMR spectrum?

SDBS, National Institute of Advanced Science and Technology.

A.  Propane

B.  Propanal

C.  Butanoic acid

D.  Ethyl ethanoate

D