Atrans alkene is more stable than a cis alkene because they have fewer steric interactions. in an elimination reaction, a geometry where the β hydrogen and the leaving group are on opposite sides of the molecule is called anti periplanar. in an sn1 mechanism, a nucleophile attacks the carbocation, forming a substitution product, while in an e1 mechanism, a base removes a β hydrogen from the carbocation, forming a new π-bond. ch3ch2br and naoh react by an mechanism. stronger bases, like hydroxide, favor reactions, whereas weaker bases, like water favor, reactions. disubstituted alkenes always have the possibility to exist as two different . reactions are regioselective, favoring formation of the more substituted and more stable alkene.