Laboratory experiments in chemistry

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. 1921 Excerpt: ...trough. Funnel. Test tubes. Materials.--Sodium nitrate. Concentrated sulfuric acid. Excelsior. White woolen yarn. Concentrated ammonium hydroxide. Copper turnings. Zinc. Ferrous sulfate solution, freshly prepared. Caution. Nitric acid is very corrosive. Do not drop it on your flesh or clothes. a. Preparation. Place about 30 g. of sodium nitrate (or potassium nitrate) on a piece of paper and fold the paper so that the solid may be slipped into the retort through the tubulure. Support the retort on the wire gauze with asbestos center, which is itself supported on a tripod. Clamp the neck of the retort in such a way (Fig. 66) that it extends into a large test tube or small flask partly immersed in cold water. Pour 20 cc. of concentrated sulfuric acid through a funnel upon the nitrate and then carefully remove the funnel without dropping acid from it. Replace the glass stopper in the tubulure. As soon as the sulfuric acid has moistened the entire mass of nitrate crystals, begin heating the retort gently. Distill at as low a temperature as possible until no more nitric acid condenses in the neck of the retort. Allow the retort to cool in position. The residue, which is. sodium (or potassium) hydrogen sulfate (NaHSO4), may be removed with warm water. Write the equation for the preparation of nitric acid. b. Properties. The nitric acid just prepared is 100% pure, and great care must be used in handling it. Pour 1-2 cc. of this acid into a test tube and insert a small, loose wad of excelsior so that it remains about an inch above the acid. Hold Fig. 66. Making nitric acid with a tubulated retort. ing the test tube in a holder, boil the acid vigorously until the vapor reaches the excelsior. Now move the test tube so as to heat the excelsior itself for a few seconds....