Zinc dust in alcoholic solution is a specific reagent in the preparation of alkenes as a

Zinc dust in alcoholic solution is a dehalogenation agent in the preparation of alkenes. As the name suggests, Zn helps to remove halogens from the alkyl dihalide. Following is the reaction that takes place when Zn dust is added to an alkyl dihalide.

${\mathrm{CH}}_2\mathrm{X}-{\mathrm{CH}}_2\mathrm{X}+\mathrm{Zn}\to {\mathrm{CH}}_2={\mathrm{CH}}_2+{\mathrm{ZnX}}_2$