<prompt> Lee Jones test is used for ?Carbolic acidArsenicCyanideLead  <response>: Ans. is c i.e., Cyanide Lee Jones test Few crystals of ferrous sulfate is added to 5 ml of the gastric content. To it, 5 drops of sodium hydroxide is added. The mixture is boiled and cooled. To it, 10 drops of 10 hydrochloric acid is added. Greenish blue colour indicates cyanide and purplish colour indicates salicylate. 