Chemical lecture experiments . , have a constricted tip of not more than 3 mm. indiameter, and not more than 10 cc. of acid should be placedin the dropping-funnel at a time. 4 HN03 = 2 H20 + 4 N02 + 02. Combustion-tubing, Jena glass ; dropping-funnel; large glass elbow;4-tube burner; pumice-stone ; asbestos paper ; large test-tube ; pneu-matic trough and cylinders. 228 CHEMICAL LECTURE EXPERIMENTS 80. Test for nitric acid. — The brown ring produced by theaction of a solution of ferrous sulphate on concentrated sul-phuric acid containing nitric acid is strik-Jft ingly shown by placing 150 cc. o
Chemical lecture experiments . , have a constricted tip of not more than 3 mm. indiameter, and not more than 10 cc. of acid should be placedin the dropping-funnel at a time. 4 HN03 = 2 H20 + 4 N02 + 02. Combustion-tubing, Jena glass ; dropping-funnel; large glass elbow;4-tube burner; pumice-stone ; asbestos paper ; large test-tube ; pneu-matic trough and cylinders. 228 CHEMICAL LECTURE EXPERIMENTS 80. Test for nitric acid. — The brown ring produced by theaction of a solution of ferrous sulphate on concentrated sul-phuric acid containing nitric acid is strik-Jft ingly shown by placing 150 cc. of sulphuric =J|§i acid containing a small quantity of potassium nitrate in a 500 cc. cylinder and allowing aconcentrated solution of ferrous sulphate toflow from a dropping-funnel through a glasstube which delivers the liquid on the surfaceof the sulphuric acid solution (Fig. 95). Inthis way the two liquids are introduced intothe cylinder without unnecessary mixing, anda deep brown ring is formed at their surfaceof Fig. 95 500 cc. cylinder ; con. H2S04 + KN03 ; FeS04 solution. HYDRAZINE 81. Reducing action on solutions of copper and silver.— Hydrazine sulphate is a strong reducing agent, causingthe reduction of alkaline solutions of copper and silversalts. A solution of cupric sulphate to which tartaric acid andpotassium hydroxide have been added is treated with asolution of hydrazine sulphate. Even in the cold somereduction is obtained, and on warming a little, cuprous oxideis precipitated. A solution of silver nitrate to which has been added suf-ficient ammonium hydroxide to redissolve the precipitatefirst formed is treated with a solution of hydrazine sulphate,which, on warming, effects the reduction with a depositionof finely divided silver. Solutions of hydrazine sulphate, AgN03, CuS04 and tartaric acid. HYDRAZOIC ACID 229 82. Action with potassium iodate. — Hydrazine sulphatereduces potassium iodate, precipitating iodine, and in theprocess of the reaction
Size: 1224px × 2043px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectchemist, bookyear1901
