The solution on acidification yields a yellow precipitate of this sulphide.
The product on acidification gives a compound C15H1205 ï¿½ H20 which is probably an oxy-methoxy-benzoyl benzoic acid.
Baeyer in 1890, by heating alizarin with fuming sulphuric acid for 24-48 hours at 35-40° C., obtained a product, which after treatment with caustic soda gave a sulphuric acid ester of quinalizarin, and this after acidification and boiling was converted into quinalizarin (Alizarin Bordeaux) or 184.108.40.206 tetra-oxyanthraquinone.
Oc 2 H 5 H Chï¿½C]](ONa) :CHï¿½000C2H5; and on acidification this last substance gives aceto-acetic ester.
Acidified copper nitrate solution is run into this cell, copper is deposited, and the more or less spent solution then passes through the linen partition, and, taking up metal from the anodes by electrolytic solution, is run out of the trough through a series of vessels filled with copper by which the silver is precipitated by simple exchange; after acidification the resulting silver-free copper solution is returned to the cathode cell for the deposition of the copper, the solution being employed again and again until too impure for use.
It is a yellow amorphous powder which is soluble in dilute alkalis, the solution on acidification giving an hydroxide, C1 4 Mo 3 (OH) 2, which is soluble in nitric acid, and does not give a reaction with silver nitrate.
With sodium ethylate in ethyl acetate solution it forms the sodium derivative of benzoyl acetone, from which benzoyl acetone, C6H5.CO.CH2.CO.CH3, can be obtained by acidification with acetic acid.
Sherard Cowper Coles patented a process in which, working with a high current density, a lead anode is used, and powdered zinc is kept suspended in the solution to maintain the proportion of zinc in the electrolyte, and so to guard against the gradual acidification of the bath.
Chromium and its salts may be detected by the fact that they give a deep green bead when heated with borax, or that on fusion with sodium carbonate and nitre, a yellow mass of an alkaline chromate is obtained, which, on solution in water and acidification with acetic acid, gives a bright yellow precipitate on the addition of soluble lead salts.