Mechanisms for (-5[1])this type of reaction (-5[1])are discerned by the parameter m in the Grunwald–Winstein equation. It’s not alkylation, but the presence of sulfur in mustard gas increases the rate of one of these (-5[1])reactions in a classic example of anchimeric (“an-kye-MER-ic”) assistance. Carbocation (“carbo-CAT-eye-on”) intermediates act as Lewis acids in one of these reactions. (-5[1])In one type of this reaction, inversion of configuration (10[1])occurs due to (10[1])a (-5[1])“backside attack.” (10[1]0[1])A pentavalent (10[1])transition state occurs (10[1])in one type of this reaction whose name indicates that it is bimolecular. High temperatures or bulky bases cause eliminations to (-5[1])be (0[1])favored over these reactions. (10[1])For 10 points, the nucleophilic SN1 and (0[5])SN2 mechanisms exemplify what type of reaction, in which one group of a compound is exchanged for another? ■END■ (10[1])