as aq.KOH in the aqueous soln it dissociates completely to give OH- ions OH- IONS ACT AS NUCLEOPHILES WHICH ATTACKS THE POSITIVE CENTRE OF ALKYL HALIDES FORMING ALCOHOLS
THIS REACTION IS SUBSTITUTION TYPE.......
as alc.KOH in alcoholic medium OH- acts as BASE .HENCE IT ABSTRACTS A THE PROTON FROM CARBON ATOM FORMING ALKENES
THIS IS ELIMINATION REACTION TYPE............
Anurag Ghosh I think in that alcoholic KOH the OH- ion is bit bulkier or it causes steric hindrance if it approaches d substrate,so it abstracts d proton from outside and satisfies itself?
Upvote·0· Reply ·2013-02-03 18:41:34Swarna Kamal Dhyawala ya we can more less say that @anurag