This article shows how knowledge of the location of univolatility lines and residue curve analysis helps in assessing the feasibility of extractive distillation of minimum-boiling (minT) or maximum-boiling (maxT) azeotropic mixtures or low-relative-volatility (low-alpha) mixtures (A B) by using a light-boiling entrainer (E), in accordance with the general feasibility criterion of Rodriguez-Donis et al. [Ind. Eng. Chem. Res. 2009, 48 (7), 3544-3559]. Considering all possible locations of the univolatility line alpha(AB), three minT azeotropic mixtures with a light entrainer (1.0-2 class), namely, ethanol-water with methanol, ethanol toluene with acetone, and methyl ethyl ketone-benzene with acetone; three maxT azeotropic mixtures with a light entrainer (1.0-1a class), namely, water-ethylenediamine with methanol, acetone-chloroform with dichlomethane, and propanoic acid-dimethyl formamide with methyl isobutyl ketone; and one low-alpha mixture with a light entrainer (0.0-1 class), namely, ethyl acetate-benzene with acetone, were studied in a stripping extractive column. For the 1.0-2 class, both A and B can be recovered as the bottom product, depending on the location of alpha(AB) = 1, which sets limiting values for the entrainer feed flow rate F-E/L-T for one of the product. In addition, the feasible region of the extractive distillation process is larger than for the azeotropic distillation process. For the 1.0-1a class, the product is either A or B, depending on the location of alpha(AB) = 1, which sets a minimum value of (F-E/L-T)min for one of the product. For the 0.0-1 class, feasibility depends on the existence alpha(AB) = 1. When it does not exist, B is the unique possible product. When it does, both A and B are products, with B below a maximum value of (F-E/L-T), B and A above a minimum value (F-E/L-T)(min,A).