Analytical reagents : standards and tests / compiled by Edmund White.

Date:
1911
Catalogue details

Licence: In copyright

Credit: Analytical reagents : standards and tests / compiled by Edmund White. Source: Wellcome Collection.

    20/194 (page 10)
    ( 1° ) aside for twenty-four hours, no turbidity or blackening should result. When mixed with half its volume of 5 per cent, potassium hydroxide solution, no darkening should immediately occur. Reaction : Should show no reaction with blue litmus paper. Trade Varieties. Absolute aloohol can be obtained containing not less than 99'5 per cent, ethyl alcohol. A weaker variety containing 97 per cent, is sometimes sold as “ absolute,” but is readily distinguished by fts specific gravity, which is about 080. In the U.S.P., alcohol of 95 per cent, by weight is official. In this oountry “ rectified spirit ” is generally understood to be the Spirit/us Rectificatus of the B.P., 'which contains 90 per cent, by volume of ethyl alcohol, and has a specific gravity of 0'834. ALCOHOL, METHYL. ch3oh. Specific gravity, 0'796 ; boiling-point, 65°. Clear, colour less fluid, miscible with water. Tests. Residue : Should leave no residue on evaporation. Acetone : No yellow colour or turbidity or odour of iodoform should be produced by the addition of caustic soda solution, and a few drops of N/10 iodine solution to 5 mils of the alcohol diluted with 40 mils water. Colour Test: Addition of large excess of strong caustic- soda solution should produce no coloration, and only the faintest yellow colour should be produced by the gradual addition of an equal volume of strong sulphuric acid. Distillation Test: Practically the whole of the alcohol should distil within 1°. Trade Varieties. Methyl alcohol, as described above, will contain not more than 0 05 to 010 per cent, of acetone, and is suitable for use in making up rtains of eosin-metihylene blue (Jenner, Leisch- mann, Romanowsky). Another variety, known as “ pure methyl alcohol,” contains 1 to 2 per cent, acetone, and has a boiling-point ranging over several degrees in coaisequeace. In commerce wood naph/tha is obtainable, captaining 70 per cent, upwards of methyl alcohol, the remainder being ace- tone, methyl acetate, allyl compounds, water, etc. A puri- fied and redtified wood naphtha is known as pyroxylic spirit. AMMONIUM CARBONATE. In white, translucent, flattened cakes. Composition vari- able, Jyu/t consisting, when freshly sublimed, of ammonium carbonate and carbamate. When exposed, it loses am-