(i) Draw the signals that would appear in the 'H NMR spectra of the following molecular fragments: R R R R R II III R can be any group. You may assume that all R groups do not contain 'H nuclei. You may also assume that the R groups do not influence the chemical shift values of the signals in the 'H NMR spectra of these molecular fragments. Comment on the multiplicities (splitting patterns), coupling constants (J values) and approximate chemical shift (8) values of each signal in the spectra you have drawn. [6 marks) (ii) The 'H NMR spectrum of ethanol (CH3CH2OH) in CDC13 (containing H20) contains the following signals: 8 4.80 (broad s, 1H), 3.60 (9, J = 8.0 Hz, 2H), 1.20 (t, J = 8.0 Hz, 3H). Explain what phenomenon gives rise to the following observations on the 'H NMR spectrum of ethanol: (a) If D20 (D = deuterium, ?H) is added to the solution of ethanol in CDC13 (containing H2O), the signal of the hydroxy group 'H nucleus (variable 8 value - appears at 8 4.80 in the above example) disappears. (b) The signal of the CH, hydrogen nuclei of ethanol in the 'H NMR spectrum appears as a quartet (9) regardless of whether or not D20 has been added. [4 marks]