Qualitative analysis / by William Briggs and R.W. Stewart.

  • William Briggs
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative analysis / by William Briggs and R.W. Stewart. Source: Wellcome Collection.

    172/180 (page 156)
    12. Simple salt. White amorphous powder, insoluble in water. Heated sub. in a hard test-tube. Swelled up; odour of burnt sugar. Black residue which effervesced with dil. HC1. On treating another portion of residue with water and filtering, the filtrate was alkaline, but did not effervesce with dil. HC1. Probably Ca, Ba or Sr Tartrate. Treated remainder of residue with HCl.—Filtered. Ex¬ amined the filtrate for the metal. Passed H2S through a part. No pp. Gp. II. absent. Added NHfJl and NHfJH to remainder. No pp. Gp. III. absent. Added (NH±)2S to part of alkaline solution.—No pp. Gp. IV. absent. Added to remainder.—White pp. Ca, Ba or Sr present. Filtered. Dissolved pp. in dil. acetic acid. Added K2CrO± to part of solution.—No pp. Ba absent. Added CaSO± to another part.—No pp. on shaking and standing. Sr absent. The metal present is, therefore, Calcium. Confirmed by (1) (NH4) 2C204—white pp. insol. in acetic acid. (2) Flame test—dull red flame. Examination for the acid. Heated original sub. with dil, H2>S04—no smell. H.COOH and CH3. COOH absent. Heated with cone. H2SO^.-—Immediate blackening with evolution of CO, C02, and S02. Tartaric acid present. Preparation of neutral solution of acid.—Boiled original sub. with Na2C03. Filtered. Neutralized filtrate with dil. HCl and warmed to remove C02. Added NaOH till just neutral to litmus. Applied the following confirmatory tests for tartaric acid. (1) CaCl2—White pp. soluble in cold NaOH. (2) AgN03.—White pp. Pp. was allowed to settle, the supernatant liquid poured off. Just sufficient ammonia was added to dissolve the pp. On heating a silver mirror was produced. The salt is Calcium Tartrate—CaC4H406.