Chromic chloride: May be prepared by dissolving hydrated chromium oxide in hydrochloric acid and evaporating off the liquid. It may also be prepared by adding, by weight, 1 part of either sodium or potassium dichromate to 6 parts of hydrochloric acid and gently heating for a few seconds to initiate the reaction. Chlorine gas will be evolved, so do this reaction is a well ventilated area.
Chromic trichloride classic method is to heat chromic oxide (Cr2O3) in a stream of sulphur chloride or carbon tet vapour in a tube furnace. Not very convenient. Dissolving Cr2O3 in concentrated hydrochloric acid and then evaporating to dryness produces a hydrate, if this is heated strongly it loses virtually all of the water but some decomposition to C2O3 occurs colouring the mass green. If the residue is heated to a high temperature, 700C seems in the right range, the chromic chloride sublimes leaving the chromic oxide behind.
I've had Cr2O3 sitting in a test tube with 30% hydrocloric acid for over 24 hours now, there seem to be nothing happening at all, the acid is still without any sign of turning Cr+3 - green. Is something wrong with the procedure Marvin mentioned or does it need high temperature or something? The difference between 30 and 37% can't be that great, can it?
I also can't see where anything I've quoted talks about adding Cr2O3 to hydrochloric acid. Nitro's method talks about chromium metal which I had previously thought not active enough to liberate hydrogen but I'm prepaired to suspend my disbelief on that count.
Pottery grade Cr2O3 is much much less reactive than the freshly precipitated hydrated oxide. Again I can't vouch for this, the closest experience I've had is with lapidary ceric oxide in my somewhat successful attempts to produce ceric sulphate, another potent oxidiser. I would be inclined to try sulphuric acid of different concentrations, starting with concentrated, and pounding the oxide into a very very find powder first. Reducing to chromium with aluminium is one possibility or its back to a furnace until you get enough in salt form to recycle.
Cr-metal from Cr2O3/Al thermite dissolves fast in 30% HCl.
MaximumTaco said:OK, so i have Cr(III) Oxide, Cr2O3, and i wish to dissolve this in conc. HCl to form Cr(III) Chloride - however, at room temperature, this reaction just doesn't seem to work readily - i would have thought it would. Would heating facilitate the desired reaction? Would the use of another acid, such as conc. Sulphuric acid, react more readily with the oxide without the need for heat?
Chromium (III) salt is prepared through the reaction of a chromium (III) compound, such as chromium (III) oxide or chromium (III) hydroxide, with a strong acid, such as hydrochloric acid or sulfuric acid. The resulting solution is then evaporated to yield solid chromium (III) salt.
Chromium (III) salt is commonly used in industrial processes, such as metal plating and pigment production. It is also used in the production of certain medicines and supplements, as well as in the tanning of leather.
The preparation of Chromium (III) salt involves the use of a reducing agent to convert Chromium (VI) to Chromium (III). This is because Chromium (VI) is toxic and must be reduced to a less harmful form. In contrast, Chromium (VI) salt can be directly prepared through the reaction of a chromium (VI) compound with an acid.
Yes, it is important to wear appropriate protective gear, such as gloves and goggles, when handling chromium (III) compounds and strong acids. It is also important to work in a well-ventilated area to avoid inhaling any fumes.
Yes, Chromium (III) salt can be prepared in a laboratory setting using the appropriate equipment and safety precautions. However, it is important to have proper training and knowledge of the chemicals being used before attempting this procedure.