- Aqueous KOH promotes nucleophilic substitution (SN1/SN2) reactions; OH− acts as the nucleophile, yielding alcohols.
- Alcoholic KOH, containing stronger alkoxide ions (RO−), acts as a stronger base, favoring E2 elimination reactions and forming alkenes.
Observe the following reaction and same reaction is carried out with the following compound: 
X and Y can be differentiated by:
A student is given one compound among the following compounds that gives positive test with Tollen's reagent. The compound is: 