DP Chemistry Questionbank

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.

Explain why tetramethylsilane (TMS) is often used as a reference standard in ¹H NMR.

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

Deduce the splitting patterns in the ¹H NMR spectrum of C₂H₅Cl.

Suggest the structural formula of this compound.

Deduce what information can be obtained from the ¹H NMR spectrum.

Predict the chemical shift and the splitting pattern seen for the hydrogens on the carbon atom circled in the diagram. Use section 27 of the data booklet.

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, ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{CH}}_2\mathrm{OH}$

Deduce the number of signals and chemical shifts with splitting patterns in the ¹H NMR spectrum of ethoxyethane. Use section 27 of the data booklet.

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

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

Predict the splitting pattern of the ¹H NMR spectrum of urea.

Outline why TMS (tetramethylsilane) may be added to the sample to carry out ¹H NMR spectroscopy and why it is particularly suited to this role.

Mass spectra A and B of the two isomers are given.

Explain which spectrum is produced by each compound using section 28 of the data booklet.

Predict the chemical shifts and integration for each signal in the ¹H NMR spectrum for ethanol using section 27 of the data booklet.

Predict the number of ¹H NMR signals, and splitting pattern of the –CH₃ seen for propanone (CH₃COCH₃) and propanal (CH₃CH₂CHO).

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

Deduce the number of signals that you would expect in the ¹H NMR spectrum of nitrobenzene and the relative areas of these.

Deduce the splitting pattern in the ¹H NMR spectrum for 1-bromopropane.

Identify the wavenumber of one peak in the IR spectrum of benzoic acid, using section 26 of the data booklet.

Identify the spectroscopic technique that is used to measure the bond lengths in solid benzoic acid.

Deduce the splitting pattern you would expect for the signals in a high resolution ¹H NMR spectrum.

2.3 ppm:

9.8 ppm:

Which can be identified using infrared (IR) spectroscopy?

A. functional groups

B. molar mass

C. 3-D configuration

D. bond angle

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

X-ray crystallography of a metal crystal produces a diffraction pattern of bright spots.

Using X-rays of wavelength 1.54 × 10⁻¹⁰ m, the first bright spots were produced at an angle θ of 22.3° from the centre.

Calculate the separation between planes of atoms in the lattice, in meters, using section 1 of the data booklet.