25 Turn over 8 This question is about the analysis of organic compounds. (a) X is an organic compound. (i) The accurate relative atomic masses, Ar , of the four elements that could make up X are shown in the table. Element Ar hydrogen, H 1.0078 carbon, C 12.0000 nitrogen, N 14.0031 oxygen, O 15.9949 X gives a molecular ion peak at m / z = 100.0522 on its mass spectrum. Which is the molecular formula of X? (1) A C7H16 B C6H12O C C6H14N D C5H8O2 (ii) The infrared spectrum of X contains major absorption wavenumber ranges at 3300–2500 cm−1, 1725–1700 cm−1 and 1669–1645 cm−1. Identify the two functional groups in X. (2) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) X has an unbranched carbon chain and does not exhibit geometric isomerism. Draw the skeletal formula of X. (1) 26 *(b) There are similarities and differences in the 13C NMR spectra and the high resolution 1H NMR spectra of isomeric organic compounds. Compare the NMR spectra of propan-1-ol with those of propan-2-ol. Include the number of peaks, relative peak areas and splitting patterns, where appropriate. Chemical shift values are not required. 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(Total for Question 8 = 10 marks)