Preparation. - By adding diluted hydrochloric or sulphuric acid to granulated zinc Zn + 2HC1 = ZnCl2 + H2.

Uses. - It is of little or no use as a remedy, and is only used as a test.

It is very frequently employed in testing for arsenic, antimony, or sulphur. When in its nascent condition it has active chemical affinities, and readily unites with these substances, forming sulphuretted, arseniuretted, or antimoniuretted hydrogen.