Step 1 Solvent Selection
For an unknown solid, the solvent is selected by experimentation. The solvent might be one or two liquids (a solvent pair). An ideal solvent is one that has a steep solubility vs temperature curve with respect to the solid. That is, the solid is very soluble in the solvent when the solution is hot (boiling), but the solid is very insoluble in the solvent when the solution is cool (room temperature). You will select one of three solvents, water, 95% ethanol, or the solvent pair t-butyl methyl ether/petroleum ether. Figure 1 shows structures of ethanol, t-butyl methyl ether and pentane