What happens when hydrochloride is added

"Hydrogen gas and iron chloride are produced" happens when hydrochloride is added.

Explanation:

The iron chloride & hydrogen gas (with bubble formation) is generated by adding hydrochloric acid to the iron filings. The iron displaces hydrogen from hydrochloric acid to form iron (II) chloride & hydrogen gas. That is a single displacement reaction. The reaction is given as follows: Fe+2HCl⟶FeCl2 + H2.

Further to conform that only these products are formed some analysis is done of the resulting solution and gas formed:

A pH measurement demonstrates that the solution becomes less acidic, thus hydrogen ions have been consumed. The addition of silver nitrate results in the formation of a white precipitate indicating that the chloride ions are still present in solution.