What distinguishes an allylic position from a vinylic position in an organic compound?

What is the primary reason for the increased acidity of allylic protons compared to alkyl protons?

Why do allylic compounds undergo SN1 and E1 reactions more rapidly than alkyl compounds?

What is the role of manganese(IV) oxide in the oxidation of allylic alcohols?

What is the function of UV light in allylic halogenation reactions?