What is the Lewis structure for HClO?

In many sites, I see that they put $\ce{O}$ in the middle, but our teacher said that we should put $\ce{O}$ near the extremity. Which is the best way?

Answer

The issue is that $\ce{HOCl}$ will dissociate, as usually, into $\ce{H+ + OCl-}$, which can only be possiblbe because $\ce{Cl}$ is formally $\ce{Cl+}$ and not the expected $\ce{Cl-}$. If $\ce{O}$ was to be put in an extremity, one would end up with $\ce{OHCl}$, which makes no sense because $\ce{H}$ cannot make two bonds, or $\ce{OClH}$, which makes no sense because $\ce{HCl}$ exists independently.

Hypohalous acids, like $\ce{HOCl}$, are a point of entry into the "weird" chemistry of halides, which at least in Euopean countries I know is not covered until late in college.