If you don't mind JCK
you know when you have any organic halide with a 2o substituted carbon, then a Sn1 reaction is favored in the presence of weak Nuc and polar protic solvent. The polar solvent is importan, since it can hydrogen bond to the intermediate carbocation that is formed via the slow rate determining step when the good leaving group which is the halide leaves. Now if you make the Nuc bulky, they get elimination reactions, and you form the most stable alkene, which is usually the most substituted one.