When a molecule of water ($\ce{H2O}$) and a molecule of hydrochloric acid ($\ce{HCl}$) react together, would they become a molecule made of molecules? What's the name for such thing? How would it be represented - just as $\ce{H2OHCl}$?

• It's quite nice question, but I heavily edited it. You can also edit if you disagree with some of changes. – Mithoron Aug 26 '15 at 23:44

The terminology you write your $\ce{H2OHCl}$ is similar to how we write water of crystallisation in a solid. If this is where your idea came from, it should be remarked that this is a distinct concept.