After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be basic or acidic to prevent the hydrolysis of salts of weak acids and weak bases, respectively. For example, magnesium ammonium phosphate hexahydrate is washed with a dilute ammonia solution. Following washing, the precipitate is dried to remove adsorbed water and electrolyte. In some cases, ignition is required to convert the precipitate to a suitable weighing form. For example, heating at 900 °C converts magnesium ammonium phosphate hexahydrate to magnesium pyrophosphate for weighing. Here, the excess water that may or may not be in the crystals depending on the levels of heating or drying prevents stoichiometric analysis. Finally, the precipitate is cooled in a desiccator and weighed.

Теги
Washing PrecipitatesDrying PrecipitatesIgnition Of PrecipitatesCoprecipitated ImpuritiesColloidal PrecipitatesElectrolyte WashingDilute Nitric AcidCommon Ion EffectLead SulfateDilute Sulfuric AcidMagnesium Ammonium Phosphate HexahydrateStoichiometric AnalysisDesiccator Cooling

Из главы 5:

article

Now Playing

5.22 : Washing, Drying, and Ignition of Precipitates

Complexometric Titration, Precipitation Titration, and Gravimetry

655 Просмотры

article

5.1 : Complexometric Titration: Overview

Complexometric Titration, Precipitation Titration, and Gravimetry

4.0K Просмотры

article

5.2 : Complexometric Titration: Ligands

Complexometric Titration, Precipitation Titration, and Gravimetry

740 Просмотры

article

5.3 : Properties of Organometallic Compounds

Complexometric Titration, Precipitation Titration, and Gravimetry

719 Просмотры

article

5.4 : EDTA: Chemistry and Properties

Complexometric Titration, Precipitation Titration, and Gravimetry

1.4K Просмотры

article

5.5 : EDTA: Conditional Formation Constant

Complexometric Titration, Precipitation Titration, and Gravimetry

542 Просмотры

article

5.6 : EDTA: Auxiliary Complexing Reagents

Complexometric Titration, Precipitation Titration, and Gravimetry

450 Просмотры

article

5.7 : EDTA: Direct, Back-, and Displacement Titration

Complexometric Titration, Precipitation Titration, and Gravimetry

1.7K Просмотры

article

5.8 : EDTA: Indirect and Alkalimetric Titration

Complexometric Titration, Precipitation Titration, and Gravimetry

560 Просмотры

article

5.9 : Complexometric EDTA Titration Curves

Complexometric Titration, Precipitation Titration, and Gravimetry

633 Просмотры

article

5.10 : Effects of EDTA on End-Point Detection Methods

Complexometric Titration, Precipitation Titration, and Gravimetry

191 Просмотры

article

5.11 : Masking and Demasking Agents

Complexometric Titration, Precipitation Titration, and Gravimetry

1.9K Просмотры

article

5.12 : Precipitation Titration: Overview

Complexometric Titration, Precipitation Titration, and Gravimetry

3.6K Просмотры

article

5.13 : Precipitation Titration Curve: Analysis

Complexometric Titration, Precipitation Titration, and Gravimetry

785 Просмотры

article

5.14 : Precipitation Titration: Endpoint Detection Methods

Complexometric Titration, Precipitation Titration, and Gravimetry

1.2K Просмотры

See More

JoVE Logo

Исследования

Образование

О JoVE

Авторские права © 2025 MyJoVE Corporation. Все права защищены