Organic Analysis - exam practice

Compound X consists of carbon, hydrogen and oxygen only. It has only one functional group.

What can be deduced about X?

The infrared spectrum of a compound with molecular formula C₁₀H₁₂O₂ includes strong peaks in the ranges 1,750 - 1,735 cm^-1 and 1,150 - 1,100 cm^-1.

The compound could be

A sample of element X is analysed using mass spectrometry. The mass spectrum obtained is shown.

What is the relative atomic mass of this sample of element X?

How many structural isomers with the molecular formula C₄H₁₀O give infra-red absorptions both at approximately 1200 cm^-1 and at approximately 3400 cm^-1?

This question concern the use of infrared (IR) spectra to identify organic compounds.

The IR absorption ranges associated with some organic functional groups are given below.

When propan-2-ol is refluxed with potassium dichromate(VI) and sulfuric acid, the product will show a peak due to

This question concern the use of infrared (IR) spectra to identify organic compounds.

The IR absorption ranges associated with some organic functional groups are given below.

When propan-1-ol is heated with potassium dichromate(VI) and sulfuric acid, the product, that is distilled off as it is formed, will show a peak due to

Bromine has two isotopes with relative isotopic masses 79 and 81.

Which of the following values for mass/charge ratio could correspond to a peak in the mass spectrum of bromine, Br₂?

You should assume the ions detected have a single positive charge.

What is correct about a mass spectrum of a compound?

CO and N₂ both have M_r values of 28.

What is the reason that CO and N₂ can be distinguished by high-resolution mass spectrometry?

The mass spectrum of ethanoic acid has a peak at m/z 45. Which species could cause this?

Which alcohol is likely to have a fragment ion at m/z = 31 in its mass spectrum?

Chlorine exists as two isotopes ³⁵Cl and ³⁷Cl in the ratio 3:1.

Which statement about peaks in the mass spectrum of Cl₂ is correct?

In a time of flight mass spectrometer, molecule X is ionised using electrospray ionisation.

What is the equation for this ionisation?

The infrared spectrum of an organic compound is shown.

Which compound produces this spectrum?

Y is an organic compound.

The accurate relative atomic masses, A_r, of the four elements that could make up Y are shown in the table.

Y gives a molecular ion peak at m/z = 100.0522 on its mass spectrum.

Which is the molecular formula of Y?

Propanal (CH₃CH₂CHO) and propanone (CH₃COCH₃) are isomers.

Which m/z peak would not be expected in the mass spectrum of propanone?