State the number of 1H NMR signals that would appear in the 1H NMR of propanal and state the ratio of the area under the peaks in which they would appear.
The compound shown below can be analysed to obtain infrared and mass spectra.
Using section 28 of the data booklet, suggest the molecular formulae of the ions responsible for peaks in the mass spectrum with the following m/e values.
a)This question is about some isomeric alcohols with the molecular formula C5H12O.
Some alcohols were heated with potassium dichromate(VI) and sulfuric acid. The organic compounds were separated from the reaction mixtures and purified.
The infrared spectra of two of these organic compounds are shown below.
Using section 26 of the data booklet, deduce the type of compound responsible for each spectrum.
Include in your answer references to wavenumbers and their corresponding bonds.
State what is meant by the term ‘fingerprint region’ on infrared spectra and explain how this can be used to identify primary, secondary and tertiary halogenoalkanes.
c)The infrared spectrum a student obtained of an organic molecule which contains carbon, hydrogen and oxygen atoms is shown below.
Use section 26 of the data booklet and information from the infrared spectrum to explain how the student deduced that the spectrum shows the presence of a carbonyl group.
d)In an experiment to prepare a sample of ethanal, CH3CHO, ethanol, C2H5OH, is reacted with acidified potassium dichromate (VI) and the reaction mixture is distilled. The infrared spectra for ethanol and ethanal are shown below.
i)State the bonds that give rise to the absorption in the ethanol spectrum at 3400 cm-1and the absorption in the ethanal spectrum at 1720 cm-1. [1]
ii)Explain why the absorption at 3400 cm-1 in the ethanol spectrum does not appear in the spectrum for ethanal. [1]
