Reaction of acetylene with hypochlorous acid In reaction of acetylene with hypochlorus acid chloro enol is intermediate, which further reacts with hypochlorous acid to form dichloro  ketone. My question is that why chloro enol does not tautomerise to form ketone. And if the chloro enlo further reacts to form dichloro ketone, then this must be the minor product. And mono chloro ketone should be major product . But thisdoes not happen . Why ?
The enol probably does tautomerize but it doesn't last. Some of the enol remains in enol form at equilibrium, and that reacts further with the hypochlorous acid.  This causes some of the keto form to revert to the enol, which then gets consumed again by the hypochlorous acid, and so on.  The selective reaction of the acid only with the enol ultimately pulls all of the keto form back to the enol and then the final, fully reacted product you see.