What is the common name for HCl?

The common name for HCl is hydrochloric acid. This substance is widely recognized in various chemical processes and is often encountered in laboratory and industrial settings. When HCl is dissolved in water, it forms hydrochloric acid, which is a strong acid used in many applications, including food processing and cleaning agents.

Hydrochloric acid derives its name from its components: "hydro-" indicates the presence of hydrogen and "chloric" comes from its chlorine content. This nomenclature follows typical conventions where acids formed from binary compounds (those consisting of only two elements) begin with "hydro-" and end with "-ic" when they are in aqueous form. The term 'hydrogen chloride' refers to the gaseous state of HCl, which is not the common term used when discussing its aqueous solution.

In summary, the designation of HCl as hydrochloric acid highlights both its chemical structure and its usage in a practical context, making it the correct answer.