[krishnaraj]

What is the product of acetlyene and HOCl reaction?
I gathered that Cl acts as electrophile and so (HCOH)=CHCl is formed.
Now two things can happen, it could tautomerize to keto form since enol form is unstable, or another molecule of HOCl can add itself, if it adds again there are two ways of adding them, both chlorine atoms could end up on the same carbon or on adjacent carbons. How do we decide what will be the final product?

[sjb]

This may depend on the number of equivalents of hypochlorite or exact conditions. Sometimes you just do the experiment and find these things out, then rationalise things that way.

Consider e.g. bond strengths, electrostatic repulsions etc.