Can someone explain How you get complete reactions?

This involves physical chemistry. Unless you just happen to know what the products of the reaction are or can intuitively deduce the products, you would have to know the bond angles and the bond strengths in order to know where the bonds will break and what ions will be present and ready to attach themselves to the broken bond sites. As a rule, triple bonds are more easily broken then doubel bonds and double bonds are more easily broken than single bonds.

In this case that you have shown, you have two very reactive ions and water. the chlorine is veery reactive and has a valence of negative one. The OCl ion is composed of two very reactive negative ions oxygen and chlorine. these two materials are very reactive and are hungry for a positive ion with which to combine. You have only one potential positive ion and that is the hydrogen. The chlorine will want one hydrogen ion and the OCl will also want one. So for each Cl and OCL you will need a water molecule. Enough hint, you're on your own.

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