Practical and analytical chemistry - Tapa blanda

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 Excerpt: ... in NH4OH, and silver bromide--AgBr, yellowish-white, slowly soluble in NH4OH. 7. KCN precipitates white silver cyanide--AgCN, soluble in excess and in concentrated HN03. 8. Heated with Na2C03 on charcoal, before the blowpipe, compounds of silver form a bright, metallic button, soluble in HN03. REACTIONS OF MERCURY as mercurous salt (Hg(ous)). Use a solution of mercurous nitrate (Hg2(N03)2). 1. HCl or soluble chlorides precipitate mercurous chloride--Hg2C12, converted by strong HNO3 into a mixture of HgC12 and Hg(N03)2, also becoming black on the addition of NH4OH, forming NH2Hg2C1. 2. H2S or NH4HS precipitates a mixture of Hg with HgS. 3. KOH or NaOH produces a black precipitate of mercurous oxide--Hg20, insoluble in excess. 4. NH4OH causes a black precipitate of mercurousammonium nitrate--NH2Hg2N03. 2NH40H + Hg2(N03)2 = NH2Hg2N03 + NH.N03 + 2H20. 5. K2Cr04 forms an orange precipitate of mercurous chromate--Hg2Cr04. 6. KI precipitates green mercurous iodide--Hg2I2. 7. Before the blowpipe, mercurous salts volatilize, some being converted into mercuric salt and mercury, both of which sublime. REACTIONS OF LEAD (Pb). Use a solution of lead acetate (Pb(C2H302)2). 1. HCI, or soluble chlorides, produce a white precipitate of lead chloride--PbC12, soluble in hot water. 2. H2S or NH4HS precipitates black lead sulphide--PbS, insoluble in HCI, soluble in hot HN03. 3. KOH or NaOH produces a white precipitate of lead hydrate--Pb(OH)2, soluble in large excess, forming potassium or sodium plumbate--K2Pb02 or Na2Pb02. 4. NH4OH precipitates white basic lead hydrate. 5. K2Cr04 produces a yellow precipitate of lead chromate--PbCr04, soluble in KOH and in strong HN03. 6. KI forms a yellow precipitate of lead iodide--Pbl2, soluble in boiling water. 7. H2S04 produces a white p...