For which reaction mechanisms—sn1, sn2, e1, or e2—are each of the following statements true? a statement may be true for one or more mechanisms. the mechanism involves carbocation intermediates. the mechanism has two steps. the reaction rate increases with better leaving groups. the reaction rate increases when the solvent is changed from to . the reaction rate depends on the concentration of only the alkyl halide. the mechanism is concerted. the reaction of with naoh occurs by this mechanism. racemization at a stereogenic center occurs. tertiary (3°) alkyl halides react faster than 2° or 1° alkyl halides. the reaction follows a second-order rate equation.