DETERMINATION OF ARSENIC.
Arsenic cannot be completely separated from either its aqueous hydrochloric acid, or from a solution to which ammonium oxalate has been added in excess. From its aqueous as well as from its oxalate solution, a portion of the metal may be separated, but if the current is passed through its hydrochloric acid solution for a sufficient length of time, all the arsenic will be volatilized as arsenious hydride (AsH3).