This organic chemistry video tutorial highlights the difference between basicity and nucleophilicity. It provides the periodic trend of base strength vs nucleophile strength and discusses the two in terms of the solvent used such as a polar protic solvent or an aprotic solvent. In addition, it highlights the relationship between steric hindrance and the strength of the base and the nucleophile. This video contains a few examples and practice problems that discusses the reaction mechanism favored by bases and nucleophiles. Bases favor elimination reactions E1 or E2 and nucleophiles favor nucleophilic substitution reactions SN1 and SN2.