Aim: To prepare and submit 20ml of strong solution of ferric chloride BPC
Apparatus: required:
- Beaker
- Conical flask
- Glass funnel
- Glass stirrer
- Measuring cylinder
Formula:
| Ingredients | Official Formula | Working Formula |
|---|---|---|
| Iron | 210g | 4g |
| Nitric acid(Concentrated) | 90ml | 1.71ml |
| Hydrochloric acid (concentrated) | 1230ml | 23.5ml |
| Water qs to | 1050ml | 20ml |
Principle:
Iron when heated with con. Hydrochloric acid it forms ferrous chloride alongside hydrogen gas. Gentle heating is preferred till evolution of hydrogen gas ceases to ensure completion of reaction.
Fe+2HCl→FeCl2
Impurities from iron such as carbon and carbides are removed by filtration. In the second stage ferrous chloride oxidizes to ferric chloride in presence of Hydrochloric acid(iron in reduced form is volatile).
2FeCl2+Cl2→2FeCl3
Further oxidation is made complete using nitric acid, since ferrous chloride is volatile.
HNO3 + 3 FeCl2 + 3 HCl → NO + 3 FeCl3 + 2 H2O
The liquid when evaporated yields ferric oxychloride precipitate due to hydrolysis of ferric chloride
Recognition of precipitate is difficult unless appreciable quantity has been formed. However, the pungent fumes of HCl are most easily recognized and are a better indication of when to cease evaporation.
FeCl3 + H2O → Fe(OH)Cl2 + HCl
A specified quantity of hydrochloric acid is then added to dissolve oxychloride in the form of ferric chloride.
Fe(OH)Cl2 + HCl → FeCl3 +H2O
Procedure:
- Add iron into a flask containing 8ml if water and 14.3ml of HCl.
- Heat gently until effervescence ceases, boil and filter un dissolved iron
- Wash the content of flask and filter
- Add 8ml of HCl to filtrate, mix and pour the solution in slow continuous stream into nitric acid(If needed with gentle heating)
- Evaporate the product, once precipitate begins to form, add HCl and sufficient water to produce 20ml
Category: Haematinic( increases haemoglobin content of blood, used to treat iron deficiency anemia)
Dose:0.3 ml
Storage: Store in a well closed container in cool place.
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