1. Considering the various intermolecular interactions possible, explain the following observations: (a) On a silica gel TLC plate eluted with ethyl acetate/acetone, 2-acetoxybenzoic acid (aspirin) elutes with a Rf = 0.51 and caffeine with a Rf = 0.20. Although aspirin is a more polar molecule, it migrates more than caffeine. Explain. (b) Methoxyethane (b.p. 7C) and 2-propanol (b.p. 83 C) are constitutional isomers with the same molecular formula, C3H8O. At room temperature 2-propanol is a colourless liquid while methoxyethane is a colourless gas. Rationalise why the two isomers exist in different states at 20 C.