Anhydrous ferric chloride is prepared by:
| A. |
heating hydrated ferric chloride at a high temperature in a stream of air |
| B. |
heating metallic iron in a stream of dry chlorine gas |
 |
| C. |
reaction of ferric oxide with HCl (aq) |
| D. |
reaction of metallic iron with HCl (aq) |
`2Fe+3Cl_2 2FeCl_3` (anhydrous) ; (A),(C),(D) do not give anhydrous `FeCl_3` but hydrated `FeCl_3.`