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Ferrous Sulphate

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  H A E M A t I N I C s Ferrous Sulphate (FeSO₄.7H₂O) molecular weight = 278 Not less than 98% not more than 103.3 N  PREPARATIONS It is obtained by dissolving iron in excess of dil. H₂SO ₄ After the effervescence stops ---> liquid is filtered, concentrated and cooled. The green crystals are formed  In all this operations undue exposure to air is prevented, because ferrous sulphate is oxidized readily on exposure to moist air and the crystal gets coated with brownish yellow ferric sulphate. Fe +  H₂SO ₄  ------>  FeSO₄ +  H₂ ↑ PROPERTIES Occurs in green crystals or crystalline powders, Astringent taste, Effloresces in dry air, In air, oxidised to ferric salt of brownish yellow color, Soluble in water, Insoluble in alcohol, When heated, decomposes to yield Ferric Oxide, Sulphur dioxide, and sulphuric acid. 2( FeSO₄.7H₂O ) + Heat -------> Fe₂O₃ + SO₂ +  H₂SO₄ + 13 H₂O Ferrous sulphate reduces the salts of silver and gold to their ...

Haematinics

H A E M A t I N I C s They   are the agents used for formation of blood to treat various types of anemia.  These include: Iron, Vitamin B 12 and Folic Acid. There are mainly two drugs or chemical that are used as haematinics : Ferrous Sulphate (FeSO₄) Ferrous Gluconate (C₁₂H₂₂O₁₄Fe.2H₂O)

Mohr's Method and its Limitations

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  Mohr's method Formation of coloured ppt Mohr's method of determination of chlorides and bromides by titration with silver nitrate. PRINCIPLE: The method involving end point detection by formation of an orange red precipitate of silver chromate (after the precipitation of AgCl is complete) using potassium chromate as an indicator is called Mohr's Precipitation titration method. chloride ion sample ---> dissolved in water ---> titrate with AgNO 3  ---> formation of white AgCl ppt. At the end point, excess drop of silver nitrate reacts with indicator and forms the orange red coloured ppt of Silver chromate. The concentration of the indicator is important. The silver chromate should start precipitating at the equivalence point, where we have the saturated solution of AgCl. From Ksp, the concentration of Ag+ at the equivalence point is 10¯⁵ M. Ksp for Ag 2 CrO 4 = 1.1 x 10¯¹²   Ksp = [Ag+] ²  . [CrO 4 ¯ ² ] (∵Ag₂CrO 4 ) ∴ 1.1 x  10¯¹² = ( 10¯⁵) ² ....

Precipitation Titration and its Type

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  Precipitation Titration The titration in which reaction between titrate and titrant results in the formation of precipitates or slightly soluble ionogens is called precipitation titration. Here the coloured particles floating in the solution is known as precipitates (ppt.)    Types of Precipitation Titration There are basically two types of Precipitation titration: 1. Argentometric Titrations:- ---> The titration in which AgNO 3  is used as titrant is called argentometric titration. 2. Mercurometric Titrations:- ---> When mercuric Nitrate is used as titrant, the titration is called mercurometric titration. ---> It can be used for the estimation of halides (chloride / bromide), thiocynate etc. ---> in this titration, the end point is not clear, so ethanolic medium is used for the titrations. Diphenly carbazone is used as an indicator which imparts blue color at the end of the titration.

Solubility product constant and its applications

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Solubility Product Constant   ---> Solubility Product is the product of the concentration of ions of the electrolyte each raised to the power of their coefficients in the balanced chemical equation in a saturated solution. ---> It has a constant value for an electrolyte at a constant temperature. ---> Solubility product constant is denoted by (Ksp) ---> To understand this concept, lets take one example: Consider the saturated solution of FeS in water. The equilibrium is represented by.... The equilibrium constant for above reaction is..... FeS is in solid state and it will not affect the equilibrium constant as it is in its standard state. So, the equilibrium constant is expressed as Ksp (Solubility Product Constant) Where [ Fe ๋ ² ] and [S¯ ² ] represent the concentration of ions in moles/liter. Here the unit of Ksp is (moles/liter) ²  The general precipitation reaction is written as  The unit of Ksp is  (moles/liter)^ a+b ๋ This is called mathematica...

Classification of Powders

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 Powders Powders are classified into 5 types: Bulk powder for internal use Bulk powder for external use Simple and Compound powder for internal use Powders enclosed in cachets and capsules Compressed powders (TABLETS) 1. Bulk Powder for Internal Use Dispensed in bulk (When accuracy isn't imp.) Contains several Doses Not supplied in wide mouthed containers that permits easy removal of spoonful of powder non potent substance are antacids and laxatives Bentonite clay for upset stomach 2. Bulk powders for external use: Meant for external use  non potent substance supplied in cardboard, glass or plastic container Dusting powders are supplied in perforated conatiners Label - FOR EXTERNAL APPLICATION ONLY Perforated container (caps bearing holes) Examples : >Snuffs                                  > Dusting powder                 >Insufflations...

Powders, Advantages and Disadvantages

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POWDERS A pharmaceutical powder is a mixture of finely divided drugs or chemicals in dry form.   Meant for both Internal and External Use. Available in crystalline or amorphous form. Particle size of powder plays an important role in physical, chemical and biological properties of the dosage forms. Relationship between Particle size and physiological properties are given below. ↓ Particle size = ↑ dissolution, absorption, and therapeutic effect (Because it will increase the surface area)                                        Advantages of Powder: can be used both Internally and Externally. More stable than liquid dosage form. A physician can prescribe a specific amount of powdered medicament depending upon the need of the patient. chance of incompactibilites are less than liquid dosage form. Rapid action because of increase in Surface area. Easily dissolved in the body fluids due to...