By mixing 3 parts of nitric, with 4 of hydrochloric acid, and afterward 25 of distilled water: the strong acids, undiluted, are left to act upon each other for twenty-four hours to insure complete decomposition and the full development of free chlorine.

2HNO3 + 6HC1 = 4H1O + 2NO + 3C12

At the same time two other compounds are formed - chloro-nitrous and chloro-nitric gas. If the acids be diluted before being mixed, the same reaction occurs, but requires several days for completion.