Elementary Treatise on Photographic Chemistry (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1882 edition. Excerpt: ...which explode when heated strongly indicate chloric acid. Brown fumes indicate hydrobromic acid, but slight brown fumes, which increase when metallic copper is placed in the liquid, indicate nitric acid. Violet fumes prove the presence of hydriodic acid. Yellow fumes of chlorine, which bleach moist litmus paper, indicate hypochlorous acid (the substance is probably chloride of lime). Effervescence, with odour of burning sulphur, indicates sulphurous acid. Odour of burning sulphur and yellow precipitate indicates hyposulphurous acid. Effervescence with inflammable gas which burns with a blue flame indicates the probable presence of oxalic acid. Gradual blackening, with evolution of inflammable gas, proves the probable presence of citric acid. Odour of vinegar indicates acetic acid. To confirm some of the preceding tests, dissolve about twenty grains of the substance in water; to a small part of the solution add barium nitrate. A white precipitate, insoluble in nitric acid, indicates sulphuric acid; yellow, soluble in nitric acid, indicates chromic acid. To another part of the solution add silver nitrate. A white precipitate, insoluble in nitric acid, indicates hydrochloric acid; yellow, insoluble in ammonia, proves the presence of hydriodic acid; cream-coloured, slightly soluble in ammonia, indicates hydrobromic add. A white precipitate, insoluble in cold nitric acid, but soluble on boiling, indicates hydrocyanic acid. A white precipitate, which blackens on standing, indicates hyposulphurous acid. To a small part of the solution add sulphate of iron, and then gradually pour down the sides of the tube strong sulphuric acid. A brown ring at the junction of the two liquids indicates nitric acid; a light blue precipitate with sulphate of iron...