An earphone jack and a mobile terminal having the same is provided so as to enable a plug to be smoothly inserted into or pulled out of an earphone jack regardless of diameter variations of the plug and the earphone jack without providing an additional part. Methods of producing decolorized homo- and co-polymers through polymerization of monomers in presence of the cobaloxime derivatives and decolorization of the produced polymer by exposing the polymer to a sorbent and, optionally, a solvent are also disclosed herein. A neck is extended from a side of the main body and connected to a rod.