5. Answer ALL parts. a) Given that a compound of molecular formula CH12O2 recorded a max of 215 nm, propose TWO different possible structures for the compound and explain your answer. (6) b) An oxygen-containing organic compound P with the molecular ion peak at a mass of 120.0575 (M), occurs with an abundance of 50%. Another peak was observed at 121.0575 (M+1) with an abundance of 4.4%. Propose a molecular formula for the compound P. (5) Using infrared and 'H NMR spectroscopy, show how you would distinguish among the four isomers of CsH9NO shown below. For EACH technique, give approximate values for TWO key distinguishing features in the spectra of each compound. HO CH3 Q CH3 -4.23 ppm H. H H. R NH H H 5 H3C.CH H H (10) d) Provide a clear explanation for why the methyl protons in the compound shown below resonate far upfield at -4.23 ppm while the ring protons resonate downfield between 7.98-8.67 ppm. H H H3C- H CH3 H N H O S -4.23 ppm H CH3 T CH3