In this discovery laboratory, students performed electrophilic aromatic substitution reactions between 1,4-dimethoxybenzene and either 2-methyl-2-butanol or 3-methyl-2-butanol with sulfuric acid as a catalyst. The carbocation from 3-methyl-2-butanol undergoes a hydride shift, and hence, both reactions afford 1,4-bis(1,1-dimethylpropyl)-2,5-dimethoxybenzene in high yields. NMR spectroscopy, infrared spectroscopy, mass spectrometry, and the melting point all indicate identical products from both reactions. Students determine the product identity from the spectroscopy results. Melting point and gas chromatography confirm that the products are identical, promoting discussion of carbocation stability and the hydride shift mechanism. (Contains 2 notes and 1 figure.)