Treating alkyl halides with aqueous $\text{KOH}$ leads to a nucleophilic substitution reaction, forming alcohols as the major product rather than alkenes . In contrast, heating alkyl halides with alcoholic $\text{KOH}$ causes a $\beta$-elimination (dehydrohalogenation) reaction, which successfully forms alkenes . Additionally, the reduction of alkynes with sodium in liquid $\text{NH}_3$ produces trans-alkenes , and the treatment of vicinal dihalides with zinc metal undergoes dehalogenation to form alkenes . Therefore, the use of aqueous $\text{KOH}$ is the incorrect method for alkene synthesis.