2-propanone. The simplest ketone. Can be used as a polar aprotic solvent in nucleophilic substitution reactions (SN2) due to its lack of hydrogen bond donors and relatively high polarity (dielectric constant = 21, dipole moment = 2.88 D). Relatively acidic (pKa 19) and undergoes keto-enol tautomerism. Cheap. Often used for cleaning glassware.