When HOCl is added to propene, the product is 1-chloro 2-propanol.My book says this is because the electrophile generated is Chloronium ion and the addition follows Markovnikov’s rule. Accepted .But when the same HOCl adds to allyl alcohol, the product I expected is 3-chloro propan 1, 2 diol. But actually, it is just the reverse; chlorine goes to the beta position. Why is it so? What is the mechanism of this reaction?