Compound E has the composition 69.8% carbon, 11.6% hydrogen and 18.6% oxygen. Its mass and 1H NMR spectra are shown below.

a. Calculate the empirical formula of E.

b. From the mass spectrum, find the molecular mass of E (ignoring the 13C peak) and hence its molecular formula.

c. Compound E reacts with 2,4-dinitrophenylhydrazine to give a yellow-orange precipitate. Draw displayed formulae for the seven possible isomers of E.

d. Compound E gives a silver mirror with Tollens’ reagent. Identify the functional group in E.

e. Use the 1H NMR spectrum to identify E. Explain your reasoning.

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a. 100 80 60 40 20 10 20 30 40 50 60 70 80 Mass-to-charge ratio (m/e) b. singlet (9H) singlet (1H) 12 11 10 9 8 7 6 5 4 3 2 10 -1 Chemical shift, 8/ ppm Absorption of energy Relative abundance