SOLUTION 18.1a
The second reaction is faster. Substrate is the same, but CH3O- is the better nucleophile (anionic vs neutral). In SN2 reactions, strength of nucleophile affects the activation energy.
The second reaction is faster. Substrate is the same, but HS- is the better nucleophile in protic solvent (larger anions are solvated less efficiently). In SN2 reactions, strength of nucleophile affects the activation energy.
