This document discusses complexometric titration, which involves titrating a metal ion with a complexing agent or chelating agent. It provides examples of different types of complexometric titrations including direct titration, back titration, and replacement titration. Assays for several substances using complexometric titration methods are described, such as magnesium sulfate using EDTA as the titrant, and calcium carbonate where the carbonate is dissolved using acid prior to titration.
The document discusses different types of complexometric titration methods including direct titration, backtitration, replacement/substitution titration, and indirect titration. Direct titration involves directly titrating a metal ion solution with EDTA. Backtitration involves adding excess EDTA and back-titrating the excess with a second metal ion. Replacement/substitution titration involves quantitatively displacing one metal ion with the metal ion being determined. Indirect titration is used for anions by first precipitating them with a metal cation before titrating the metal with EDTA. The document also discusses titration curves in complexometric titration and EDTA as the most commonly used titrant.
Modified limit tests for chlorides and sulphates.EXCELRA
This document describes a modified limit test for chlorides and sulphates. For chlorides, the test is based on the reaction between silver nitrate and chloride ions to form a silver chloride precipitate in dilute nitric acid. The turbidity produced is compared to a standard solution. For sulphates, barium chloride reacts with sulphate ions in the presence of acetic acid to form a barium sulphate precipitate. The opalescence produced is compared to a standard solution containing a known amount of sulphate. Detailed procedures are provided for preparing reagents and performing the tests on samples and standards.
The document discusses the benefits of meditation for reducing stress and anxiety. Regular meditation practice can help calm the mind and body by lowering heart rate and blood pressure. Studies have shown that meditating for just 10-20 minutes per day can have significant positive impacts on both mental and physical health over time.
more chemistry contents are available
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EDTA Titration
This document describes procedures for estimating the purity of magnesium sulfate and calcium gluconate. It first details the preparation of a 0.05 M disodium edetate solution and its standardization. For magnesium sulfate estimation, 0.3 g of the compound is dissolved and titrated against the disodium edetate solution. The volume used is used to calculate purity percentage. For calcium gluconate estimation, an accurately measured volume equivalent to 0.5 g of the compound is titrated against disodium edetate after the addition of magnesium sulfate and ammonia solutions. The volume used is then used to calculate the amount of calcium gluconate present.
Diazotization titrations involve the reaction of primary aromatic amines with sodium nitrite in acidic solution to form unstable diazonium salts. This reaction can be used for both qualitative and quantitative analysis of compounds containing amino groups. The endpoint is detected using an external indicator like starch-iodide paper, which detects excess nitrous acid after all the aromatic amine has reacted. Some common compounds that can be assayed via diazotization titration include dapsone, sulphamethoxazole, and benzocaine.
The document discusses different types of complexometric titration methods including direct titration, backtitration, replacement/substitution titration, and indirect titration. Direct titration involves directly titrating a metal ion solution with EDTA. Backtitration involves adding excess EDTA and back-titrating the excess with a second metal ion. Replacement/substitution titration involves quantitatively displacing one metal ion with the metal ion being determined. Indirect titration is used for anions by first precipitating them with a metal cation before titrating the metal with EDTA. The document also discusses titration curves in complexometric titration and EDTA as the most commonly used titrant.
Modified limit tests for chlorides and sulphates.EXCELRA
This document describes a modified limit test for chlorides and sulphates. For chlorides, the test is based on the reaction between silver nitrate and chloride ions to form a silver chloride precipitate in dilute nitric acid. The turbidity produced is compared to a standard solution. For sulphates, barium chloride reacts with sulphate ions in the presence of acetic acid to form a barium sulphate precipitate. The opalescence produced is compared to a standard solution containing a known amount of sulphate. Detailed procedures are provided for preparing reagents and performing the tests on samples and standards.
The document discusses the benefits of meditation for reducing stress and anxiety. Regular meditation practice can help calm the mind and body by lowering heart rate and blood pressure. Studies have shown that meditating for just 10-20 minutes per day can have significant positive impacts on both mental and physical health over time.
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
EDTA Titration
This document describes procedures for estimating the purity of magnesium sulfate and calcium gluconate. It first details the preparation of a 0.05 M disodium edetate solution and its standardization. For magnesium sulfate estimation, 0.3 g of the compound is dissolved and titrated against the disodium edetate solution. The volume used is used to calculate purity percentage. For calcium gluconate estimation, an accurately measured volume equivalent to 0.5 g of the compound is titrated against disodium edetate after the addition of magnesium sulfate and ammonia solutions. The volume used is then used to calculate the amount of calcium gluconate present.
Diazotization titrations involve the reaction of primary aromatic amines with sodium nitrite in acidic solution to form unstable diazonium salts. This reaction can be used for both qualitative and quantitative analysis of compounds containing amino groups. The endpoint is detected using an external indicator like starch-iodide paper, which detects excess nitrous acid after all the aromatic amine has reacted. Some common compounds that can be assayed via diazotization titration include dapsone, sulphamethoxazole, and benzocaine.
Volumetric Analysis
Types of titration
Acid- Base Theory
Reaction, End Point & Indicators
Acid- Base titration
Titration curve
Non- Aqueous Titration
Precipitation Titration
Complexometric Titration
Oxidation- Reduction Titration,
Calculation. Errors
General Informations,
Complexometric titration involves the titration of a metal ion solution with a chelating agent or ligand until the metal ion forms a stable complex. It is useful for determining mixtures of metal ions. The document discusses various types of complexometric titrations including direct titration, back titration, and replacement titration. It also covers the use of metal ion indicators, masking and demasking reagents, and provides examples of complexometric titration for determining compounds like magnesium sulfate, calcium gluconate, and auric ions in ores.
Iodometry and iodimetry are titration methods that involve the reaction of iodine with an analyte. In iodometry, the analyte is an oxidizing agent that liberates iodine, which is then titrated with a standard thiosulfate solution. In iodimetry, the analyte is a reducing agent that is directly titrated with a standard iodine solution. Starch is commonly used as an indicator for the titrations. Iodometric and iodimetric titrations cannot be performed in strong acidic or basic conditions due to side reactions involving iodine and interference with the indicators. The methods are useful for determining concentrations of substances like vitamin C,
This document describes the limit test for iron according to the Indian Pharmacopoeia. The test involves comparing the color produced by reacting a sample with thioglycolic acid in an ammonical citrate buffer to the color produced by a standard iron solution under the same conditions. If the color produced by the sample is less than the standard, it passes the limit test for iron. If the color is greater than the standard, it fails the limit test. The test is sensitive and uses citric acid to eliminate interference from other metal cations.
This document describes the Gutzeit test for detecting arsenic. The test works by first converting any arsenic in a sample into arsenious acid, then reducing it to arsine gas. Mercuric chloride paper placed in the apparatus will turn yellow if arsine gas is present, indicating the presence of arsenic in the original sample. The document provides details of the test apparatus, reagents used, procedure, and precautions to get accurate results and avoid contamination.
Non-aqueous titration has several advantages over aqueous titration including enabling the titration of organic acids and bases that are insoluble in water. Key types of non-aqueous solvents used in titration include aprotic, protogenic, protophillic, and amphiprotic solvents. Common indicators used in non-aqueous titration include crystal violet and oracet blue B. Example applications of non-aqueous titration include determination of active ingredients in pharmaceutical preparations like ephedrine and codeine. Proper preparation and standardization of titrants such as perchloric acid in acetic acid or potassium methoxide in toluene-methanol is important for accurate non-aqueous tit
This document describes the procedure for performing a limit test for sulphate according to the Indian Pharmacopoeia. A barium sulphate reagent is prepared containing barium chloride, potassium sulphate, alcohol and water. Standard sulphate solutions are also prepared. The test involves adding nitric acid and the reagent to samples and standards, observing any turbidity formed, and comparing the sample to the standard. If the sample turbidity is less than the standard, it passes the limit test, and if greater, it fails the test.
Complexometric titration involves the formation of a soluble complex between the analyte metal ion and the titrant. EDTA is commonly used as the chelating agent in the titrant. EDTA forms stable 1:1 complexes with metal ions, allowing for accurate determination of the equivalence point. Metallochromic indicators are used to signal the endpoint, changing color as the metal ion is removed from solution by complexation with EDTA. Selectivity can be improved through methods like masking interfering ions with reagents before titration or controlling the pH.
The document provides information about diazotization titrations. It discusses the principle, theory, procedure, end point detection, factors affecting, applications, and advantages/disadvantages of diazotization titrations. The key points are:
- Diazotization titrations involve the reaction of a primary aromatic amine with sodium nitrite in acidic medium to form a diazonium salt, which is then titrated.
- The end point is detected using an external indicator like starch iodide paper or electrochemically.
- Factors like acid concentration, temperature, and reaction time must be controlled.
- It can be used to determine drugs and compounds containing
This document discusses oxidation-reduction (redox) reactions and concepts including definitions of oxidation and reduction in terms of gaining or losing electrons, oxygen, and hydrogen. It provides examples of redox reactions and identifies the oxidizing agent and reducing agent in reactions. It also discusses oxidation numbers and how to balance redox equations using the oxidation number change method. Finally, it discusses redox titrations and the specific methods of iodimetry and iodometry which involve the use of iodine as the titrant or analyte.
This document discusses various redox titration methods including permanganometry, dichrometry, cerimetry, iodimetry, and bromatometry. It defines oxidation, reduction, and redox reactions. It explains how to calculate equivalent weights of oxidizing and reducing agents and different methods to detect the endpoint of a redox titration including using internal indicators, self indicators, external indicators, and instrumental methods. It provides examples of applications for each type of redox titration.
This document discusses non-aqueous titrations, which are used to analyze organic acids and bases that are insoluble or weakly reactive in water. It describes the principles, reasons for using non-aqueous titrations, common solvents like acetic acid, and provides examples of procedures to titrate drugs like ephedrine hydrochloride and sodium benzoate. The key steps involve dissolving the analyte in a non-aqueous solvent, titrating with an acid or base, and determining the endpoint using an indicator reaction.
Diazotization TITRATION FOR PG NOTES VERY USEFUL prakash64742
The document discusses the principles and applications of diazotization titration. Diazotization involves the reaction of an aromatic primary amine with sodium nitrite in acidic medium to form a diazonium salt. The titration endpoint is determined using an indicator reaction that detects excess nitrous acid. Common applications described include assays of benzocaine, dapsone, and isocarboxazid which involve diazotization and detection of the endpoint with starch-iodide paper. Diazotization titration can be used to analyze many sulfa drugs and other pharmaceuticals containing aromatic amine groups.
This document discusses non-aqueous titration including reasons for using non-aqueous solvents, common solvent types, and examples of acidimetry and alkalimetry titrations. Protogenic, protophilic, and aprotic solvents are described. Acidimetry involves titrating weak bases like ephedrine HCl with perchloric acid in glacial acetic acid. Alkalimetry involves titrating weak acids like sodium benzoate with sodium methoxide in DMF. The document provides procedures for standardizing a perchloric acid solution and estimating the percentage of ephedrine HCl and sodium benzoate in samples.
The document describes the limit test for lead, which determines the allowable limit of heavy metal lead in a sample. The test involves reacting the sample with dithizone, which forms a violet-colored lead dithizonate complex in the presence of lead. The intensity of color in the sample is compared to that of a standard lead solution treated the same way. If the sample solution is less colored than the standard, the sample passes the lead limit test. The test is useful for detecting trace amounts of lead impurity from sources like equipment, storage containers, or packaging materials used during manufacturing or storage of medical compounds.
This document discusses non-aqueous titrations. It describes how non-aqueous solvents are used to titrate weakly acidic or basic substances when they are insoluble or have comparable strength to water. Examples of titrating primary amines like methyldopa using perchloric acid in acetic acid are provided. The document also lists various solvent types, reaction theory, standardization of perchloric acid and choice of indicators for non-aqueous titrations.
The document provides instructions for performing an assay of calcium gluconate by complexometry, including preparing standard EDTA and magnesium sulfate solutions, titrating calcium gluconate against EDTA while using magnesium and an indicator to identify the endpoint, and calculating the percentage purity of calcium gluconate based on the titration results. The titration is a replacement complexometric titration that uses the stable magnesium-indicator complex to indirectly determine the endpoint of the calcium-EDTA reaction.
This document discusses various types of redox titrations and indicators used. It describes the preparation and standardization of common redox titrants like potassium manganate(VII), iodine, potassium dichromate, potassium bromate and ceric ammonium sulfate. Examples of titrations included are standardization of KMnO4 with sodium oxalate or sodium thiosulfate, iodine with sodium thiosulfate or arsenic trioxide, and sodium thiosulfate with potassium iodate. The document also covers redox indicators and conditions for iodometric titrations.
Complexometric TITRATION FOR PG IST SEM prakash64742
This document discusses complexometric titrations, which involve the titration of a metal ion with a complexing agent. It provides details on different types of complexometric titrations including direct titration, back titration, and replacement titrations. Examples are given of assays for magnesium sulfate using direct titration and calcium carbonate using back titration. Complexometric titrations find wide applications in determining metal ions in medical and water samples.
This document provides instructions for determining the concentration of magnesium (Mg) in an unknown sample by titrating with ethylenediaminetetraacetic acid (EDTA). The EDTA solution is standardized against a zinc standard solution. Magnesium in the unknown sample forms a complex with Eriochrome Black T indicator, changing color. When all the magnesium has been chelated by EDTA, the indicator changes to a clear blue, signaling the titration endpoint. Students will titrate the unknown sample with standardized EDTA and calculate the percentage of magnesium in the prepared unknown sample diluted to 100 mL.
Volumetric Analysis
Types of titration
Acid- Base Theory
Reaction, End Point & Indicators
Acid- Base titration
Titration curve
Non- Aqueous Titration
Precipitation Titration
Complexometric Titration
Oxidation- Reduction Titration,
Calculation. Errors
General Informations,
Complexometric titration involves the titration of a metal ion solution with a chelating agent or ligand until the metal ion forms a stable complex. It is useful for determining mixtures of metal ions. The document discusses various types of complexometric titrations including direct titration, back titration, and replacement titration. It also covers the use of metal ion indicators, masking and demasking reagents, and provides examples of complexometric titration for determining compounds like magnesium sulfate, calcium gluconate, and auric ions in ores.
Iodometry and iodimetry are titration methods that involve the reaction of iodine with an analyte. In iodometry, the analyte is an oxidizing agent that liberates iodine, which is then titrated with a standard thiosulfate solution. In iodimetry, the analyte is a reducing agent that is directly titrated with a standard iodine solution. Starch is commonly used as an indicator for the titrations. Iodometric and iodimetric titrations cannot be performed in strong acidic or basic conditions due to side reactions involving iodine and interference with the indicators. The methods are useful for determining concentrations of substances like vitamin C,
This document describes the limit test for iron according to the Indian Pharmacopoeia. The test involves comparing the color produced by reacting a sample with thioglycolic acid in an ammonical citrate buffer to the color produced by a standard iron solution under the same conditions. If the color produced by the sample is less than the standard, it passes the limit test for iron. If the color is greater than the standard, it fails the limit test. The test is sensitive and uses citric acid to eliminate interference from other metal cations.
This document describes the Gutzeit test for detecting arsenic. The test works by first converting any arsenic in a sample into arsenious acid, then reducing it to arsine gas. Mercuric chloride paper placed in the apparatus will turn yellow if arsine gas is present, indicating the presence of arsenic in the original sample. The document provides details of the test apparatus, reagents used, procedure, and precautions to get accurate results and avoid contamination.
Non-aqueous titration has several advantages over aqueous titration including enabling the titration of organic acids and bases that are insoluble in water. Key types of non-aqueous solvents used in titration include aprotic, protogenic, protophillic, and amphiprotic solvents. Common indicators used in non-aqueous titration include crystal violet and oracet blue B. Example applications of non-aqueous titration include determination of active ingredients in pharmaceutical preparations like ephedrine and codeine. Proper preparation and standardization of titrants such as perchloric acid in acetic acid or potassium methoxide in toluene-methanol is important for accurate non-aqueous tit
This document describes the procedure for performing a limit test for sulphate according to the Indian Pharmacopoeia. A barium sulphate reagent is prepared containing barium chloride, potassium sulphate, alcohol and water. Standard sulphate solutions are also prepared. The test involves adding nitric acid and the reagent to samples and standards, observing any turbidity formed, and comparing the sample to the standard. If the sample turbidity is less than the standard, it passes the limit test, and if greater, it fails the test.
Complexometric titration involves the formation of a soluble complex between the analyte metal ion and the titrant. EDTA is commonly used as the chelating agent in the titrant. EDTA forms stable 1:1 complexes with metal ions, allowing for accurate determination of the equivalence point. Metallochromic indicators are used to signal the endpoint, changing color as the metal ion is removed from solution by complexation with EDTA. Selectivity can be improved through methods like masking interfering ions with reagents before titration or controlling the pH.
The document provides information about diazotization titrations. It discusses the principle, theory, procedure, end point detection, factors affecting, applications, and advantages/disadvantages of diazotization titrations. The key points are:
- Diazotization titrations involve the reaction of a primary aromatic amine with sodium nitrite in acidic medium to form a diazonium salt, which is then titrated.
- The end point is detected using an external indicator like starch iodide paper or electrochemically.
- Factors like acid concentration, temperature, and reaction time must be controlled.
- It can be used to determine drugs and compounds containing
This document discusses oxidation-reduction (redox) reactions and concepts including definitions of oxidation and reduction in terms of gaining or losing electrons, oxygen, and hydrogen. It provides examples of redox reactions and identifies the oxidizing agent and reducing agent in reactions. It also discusses oxidation numbers and how to balance redox equations using the oxidation number change method. Finally, it discusses redox titrations and the specific methods of iodimetry and iodometry which involve the use of iodine as the titrant or analyte.
This document discusses various redox titration methods including permanganometry, dichrometry, cerimetry, iodimetry, and bromatometry. It defines oxidation, reduction, and redox reactions. It explains how to calculate equivalent weights of oxidizing and reducing agents and different methods to detect the endpoint of a redox titration including using internal indicators, self indicators, external indicators, and instrumental methods. It provides examples of applications for each type of redox titration.
This document discusses non-aqueous titrations, which are used to analyze organic acids and bases that are insoluble or weakly reactive in water. It describes the principles, reasons for using non-aqueous titrations, common solvents like acetic acid, and provides examples of procedures to titrate drugs like ephedrine hydrochloride and sodium benzoate. The key steps involve dissolving the analyte in a non-aqueous solvent, titrating with an acid or base, and determining the endpoint using an indicator reaction.
Diazotization TITRATION FOR PG NOTES VERY USEFUL prakash64742
The document discusses the principles and applications of diazotization titration. Diazotization involves the reaction of an aromatic primary amine with sodium nitrite in acidic medium to form a diazonium salt. The titration endpoint is determined using an indicator reaction that detects excess nitrous acid. Common applications described include assays of benzocaine, dapsone, and isocarboxazid which involve diazotization and detection of the endpoint with starch-iodide paper. Diazotization titration can be used to analyze many sulfa drugs and other pharmaceuticals containing aromatic amine groups.
This document discusses non-aqueous titration including reasons for using non-aqueous solvents, common solvent types, and examples of acidimetry and alkalimetry titrations. Protogenic, protophilic, and aprotic solvents are described. Acidimetry involves titrating weak bases like ephedrine HCl with perchloric acid in glacial acetic acid. Alkalimetry involves titrating weak acids like sodium benzoate with sodium methoxide in DMF. The document provides procedures for standardizing a perchloric acid solution and estimating the percentage of ephedrine HCl and sodium benzoate in samples.
The document describes the limit test for lead, which determines the allowable limit of heavy metal lead in a sample. The test involves reacting the sample with dithizone, which forms a violet-colored lead dithizonate complex in the presence of lead. The intensity of color in the sample is compared to that of a standard lead solution treated the same way. If the sample solution is less colored than the standard, the sample passes the lead limit test. The test is useful for detecting trace amounts of lead impurity from sources like equipment, storage containers, or packaging materials used during manufacturing or storage of medical compounds.
This document discusses non-aqueous titrations. It describes how non-aqueous solvents are used to titrate weakly acidic or basic substances when they are insoluble or have comparable strength to water. Examples of titrating primary amines like methyldopa using perchloric acid in acetic acid are provided. The document also lists various solvent types, reaction theory, standardization of perchloric acid and choice of indicators for non-aqueous titrations.
The document provides instructions for performing an assay of calcium gluconate by complexometry, including preparing standard EDTA and magnesium sulfate solutions, titrating calcium gluconate against EDTA while using magnesium and an indicator to identify the endpoint, and calculating the percentage purity of calcium gluconate based on the titration results. The titration is a replacement complexometric titration that uses the stable magnesium-indicator complex to indirectly determine the endpoint of the calcium-EDTA reaction.
This document discusses various types of redox titrations and indicators used. It describes the preparation and standardization of common redox titrants like potassium manganate(VII), iodine, potassium dichromate, potassium bromate and ceric ammonium sulfate. Examples of titrations included are standardization of KMnO4 with sodium oxalate or sodium thiosulfate, iodine with sodium thiosulfate or arsenic trioxide, and sodium thiosulfate with potassium iodate. The document also covers redox indicators and conditions for iodometric titrations.
Complexometric TITRATION FOR PG IST SEM prakash64742
This document discusses complexometric titrations, which involve the titration of a metal ion with a complexing agent. It provides details on different types of complexometric titrations including direct titration, back titration, and replacement titrations. Examples are given of assays for magnesium sulfate using direct titration and calcium carbonate using back titration. Complexometric titrations find wide applications in determining metal ions in medical and water samples.
This document provides instructions for determining the concentration of magnesium (Mg) in an unknown sample by titrating with ethylenediaminetetraacetic acid (EDTA). The EDTA solution is standardized against a zinc standard solution. Magnesium in the unknown sample forms a complex with Eriochrome Black T indicator, changing color. When all the magnesium has been chelated by EDTA, the indicator changes to a clear blue, signaling the titration endpoint. Students will titrate the unknown sample with standardized EDTA and calculate the percentage of magnesium in the prepared unknown sample diluted to 100 mL.
Learning objectives
Introduction
Complexing agents
Complexing Titration using EDTA
Need for Maintenance of pH
pH Indicators used in complexometric Titrations
Types of EDTA Titration
Factors Influencing EDTA reaction
Masking and demasking agents
Conclusion
Reference
• A chelate is formed when a metal ion coordinates with two (or more) donor groups of a single ligand. Tertiary amine compounds such as ethylenadiaminetetraacetic acid (EDTA) are widely used for the formation of chelates.
• Complexometric titrations with EDTA have been reported for the analysis of nearly all metal ions The endpoint of the titration is determined by the addition of Eriochrome Black T, which forms a colored chelate with Mg 2+ and undergoes a color change when the Mg 2+ is released to form a chelate with EDTA
This document discusses complexometric titration, which involves titrating a metal ion with a complexing or chelating agent. It describes different types of complexometric titrations including direct titration, back titration, and replacement titration. It also discusses metal ion indicators, masking and demasking agents, and provides examples of standardizing EDTA and estimating magnesium sulfate and calcium gluconate through complexometric titration.
COMPLEXOMETRIC TITRATION OR CHEALATOMETRIC TITRATIONPoonam Aher Patil
Complexometric titration involves using a ligand such as EDTA that forms stable complexes with metal ions to determine the endpoint of a titration. EDTA is commonly used as the titrant because it forms strong complexes with many metal ions. Complexometric indicators that undergo a color change are used to detect the endpoint when the metal ion is completely bound by EDTA. Common applications include assays to determine the concentration of metal ions like magnesium, calcium, and aluminum in samples.
Applications of Edta Titration - Kshetra K LBebeto G
This document discusses complexometric titration and EDTA titration. It describes the key aspects of complexometric titration including the formation of metal-ligand complexes and chelates. It then focuses on EDTA titration, explaining that EDTA is a common chelating agent used in analytical chemistry due to its ability to form stable complexes with many metal ions. The document outlines the applications of EDTA titration for determining concentrations of metal ions in solution and its use in organic analysis, medicine, and water treatment.
Application of complexometric, aquametric & amperometric titrationsKamruzzaman Siam
1. Complexometric titrations involve titrating metal ions with chelating agents like EDTA.
2. Applications include direct titration of metals like Cu and Zn as well as back titration, replacement titration, and indirect titration for metals that cannot be directly titrated.
3. Aquametric titrations determine the water content of samples, important for applications like soil quality analysis, food quality control, and environmental monitoring.
1. This document discusses various oxidation-reduction titration methods including those using ceric ammonium sulfate, potassium iodate, potassium bromate, and titanous chloride as titrants.
2. Preparation and standardization procedures are provided for 0.1N ceric ammonium sulfate, 0.05M potassium iodate, 0.1N potassium bromate, and titanous chloride solutions.
3. Examples of titrations discussed include assays of ferrous fumarate, acetomenaphthone, ferrous gluconate tablets using ceric ammonium sulfate; assays of benzalkonium chloride and hydralazine hydrochloride using potassium iodate; and assays
Complexometric titration involves the titration of a metal ion with EDTA (ethylene diamine tetraacetic acid) where a colored complex is formed at the endpoint. There are several types of complexometric titrations including direct titration where the metal ion is directly titrated with EDTA, back titration where excess EDTA is added and then titrated with another metal ion, and replacement titration where the metal ion displaces another metal ion from an EDTA complex which is then titrated. Complexometric titrations can be used to determine mixtures of metal ions and are useful because EDTA forms very stable complexes with most metal ions.
This document describes a procedure for determining water hardness through titration with EDTA. Water hardness is defined as the calcium and magnesium ion content and is reported in parts per million (ppm) of calcium carbonate. The titration uses EDTA to chelate calcium and magnesium ions until the indicator Eriochrome Black T changes color, signaling the endpoint. Standard solutions of calcium carbonate and EDTA are prepared and used to determine the concentration of EDTA and calculate water hardness based on the volume of EDTA needed to reach the endpoint in a sample.
The pptx on complexometric titrations, EDTA titration, Why EDTA is used in complexometric titration, Classification of EDTA titration, EDTA titration curve etc.
Complexometric titration involves the titration of a metal ion with a complexing agent like EDTA. The end point is detected using an indicator that changes color when the metal ion forms a complex with the titrant. There are different types of complexometric titrations including direct titration, back titration, and replacement titration that are used depending on the solubility and stability of the metal-complex formed. Complexing agents can be unidentate, bidentate or polydentate ligands that bind to the metal ion.
The document discusses several antacids including calcium carbonate, aluminium hydroxide gel, magnesium trisilicate, magnesium carbonate, sodium bicarbonate, potassium citrate, and bismuth carbonate. It provides details on the preparation, properties, assays, and uses of each antacid. The antacids are classified based on their inorganic elemental composition such as calcium, magnesium, aluminium, and sodium containing antacids. Combination antacids like magaldrate are also mentioned.
Complexometric titration involves titrating a metal ion with a complexing agent like EDTA. Magnesium sulfate can be estimated by direct titration with EDTA in the presence of ammonia-ammonium chloride buffer using an indicator. The magnesium ions form a complex with EDTA until the equivalence point is reached, indicated by a color change of the indicator. This direct titration method provides an accurate determination of the magnesium content in magnesium sulfate.
This document describes a procedure to determine the acidity of a water sample through titration with sodium hydroxide solution. The acidity is measured as both mineral acidity at pH 3.7 using methyl orange indicator and total acidity at pH 8.3 using phenolphthalein indicator. Dissolved carbon dioxide is usually the major contributor to acidity in surface waters. The titration results are used to calculate and report the acidity levels in the sample as mg/L of calcium carbonate equivalent. High acidity can interfere with water treatment and affect aquatic life.
CHELATING RADIOMETRIC TITRATIONS BY ION EXCHANGE FOR DETERMINATION OF TRACES ...AneesaZafar
CHELATING RADIOMETRIC TITRATIONS BY ION EXCHANGE FOR DETERMINATION OF TRACES OF METALS. THE DATA IS TAKEN FROM RESEARCH ARTICLE. IF ARTICLE IS NEEDED, JUST WRITE IT DOWN
This document discusses complexometric titration, which uses the formation of a colored complex to indicate the endpoint of a titration. It specifically focuses on the use of EDTA as a common titrant. Key points discussed include:
- EDTA donates six electrons to form coordinate covalent bonds with cationic metals. Disodium EDTA is commonly used.
- Other complexing agents mentioned include DTPA and EGTA.
- Masking and demasking agents are used to determine individual metal ions when multiple are present. Masking prevents interaction while demasking breaks existing complexes.
- Common indicators used in complexometric titrations include Eriochrome black T, Calmagite
PCR, HEPARIN SODIUM NOTES FOR MPHARM IST SEM prakash64742
This document presents information on heparin sodium and polymerase chain reaction (PCR). It discusses that heparin is a glycosaminoglycan used as an anticoagulant drug and its mechanism of action involves regulating blood clotting and other biological processes. The document also describes the bioassay method used to determine the potency of heparin sodium samples. It then provides details on PCR, including that it is an in vitro technique used to amplify specific DNA sequences, and explains the three main steps of PCR: DNA denaturation, primer annealing, and DNA extension.
This document discusses elemental analysis techniques used to identify potential elemental impurities in pharmaceuticals. It describes speciation analysis, which separates and quantifies different chemical forms of an element. Several instrumental methods are discussed for identifying elemental impurities, including atomic absorption spectrometry (AAS), X-ray fluorescence spectrometry (XRF), inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS). The principles, instrumentation, and sample analysis procedures of AAS and XRF are explained in further detail.
This document summarizes a seminar presentation on impurities and stability studies. It defines impurities as any component of a drug substance that is not the defined chemical entity. Impurities are classified as organic, inorganic, or residual solvents. Organic impurities can arise from manufacturing processes or storage and include starting materials, byproducts, and degradation products. Inorganic impurities result from manufacturing and include reagents, metals, and salts. Residual solvents are volatile organic chemicals used in drug substance synthesis. The document also discusses ICH guidelines for qualifying impurities based on safety testing and provides a decision tree for conducting safety studies of drug substances.
This document provides information on the preparation and potency determination of oxytocin and human antihaemophilic vaccine. It describes that oxytocin is obtained from pituitary glands and stimulates uterine contraction and milk ejection. Its potency is determined by comparing its activity to a standard preparation in assays measuring blood pressure depression in chickens. The document also describes that human antihaemophilic vaccine is prepared from human plasma to be rich in clotting factor VIII. Its potency is determined by comparing the amount needed to reduce clotting time to that of a standard preparation in an assay using citrated plasma.
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Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
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2. 2
•INTRODUCTION:
Complexometric titration is a type of
titration based on complex formation
between the analyte(metal ion) and titrant
(complexing agents).
• Complexometric titrations are particularly
useful for determination of a mixture of
different metal ions in solution. An
indicator with a marked color change is
usually used to detect the end-point of the
titration.
3. 3
Complexometric titration is the volumetric
method of analysis in which the simple metal
ion is converted into complex by addition of
reagent known as ligand or complexing agent
and is used to estimate polyvalent ions i.e.,
divalent, trivalent.
E.g.:-
4. LEWIS DEFENITION FOR COMPLEXOMETRIC
TITRATION
By Lewis defenition ,complexation is an acid-base
reaction between a ligand ,a Lewis base or electron
donor , and the metal ion, a Lewis acid or electron
acceptor.
The nature of the chemichal bond between the metal
ion and the ligand may vary from covalent to ionic.
There is a specific number of ligands that are bound to
each metal ion . This is termed as the co-ordination
number and usually a characteristic for each metal ion
5. Metal ion Co-ordination number
Silver I
Copper I
Mercury I
2
2
2
Silver II 4
Zinc II
Magnesium II
Cobalt II
Nickel
4 or 6
Aluminium III 6
Calcium II 6
Lead IV 6
Iron II and Iron III 6
Barium II 6
6. Cu2+
+ C C
H
NH2
O
OHH2
Glycine
Cu
O
N
H
O
N
H
CH2H2C
C C
O
O
+ 2H+
• Chelate: when a metal ion coordinates with
two or more donor groups of a single ligand to
form a five- or six-member heterocyclic ring.
• Unidentate: a ligand that has a single donor
group Ex: NH3
• Bidentate: a ligand that has two groups
available for covalent bonding Ex: glycine
• Tridentate, tetradentate, ……
7. Structure of H4Y and its
dissociation products.
Note that the fully
protonated species H4Y
exists as the double
zwitterion with the
amine nitrogens and
two of the carboxylic
acid groups protonated.
The first two protons
dissociate from the
carboxyl groups, while
the last two come from
the amine groups.
8. Structure of a
metal/EDTA
complex. Note
that EDTA
behaves here as a
hexadentate
ligand in that six
donor atoms are
involved in
bonding the
divalent metal
cation.
9. § Complexes of EDTA and Metal Ions
The reagent combines with metal ions in a 1:1
ratio regardless of the charge on the cation.
Ag+
+ Y4-
AgY3-
Al3+
+ Y4-
AlY-
Mn+
+ Y4-
MY(n-4)+
KMY=
[MY(n-4)+
]
[Mn+
] [Y4-
]
10. 10
Some of the basic considerations
Complexometric titrations are particularly useful for the
determination of a mixture of different metal ions in solutions.
If Complex formed is water soluble and stable those Water soluble
complexes are called sequestering agent.
If a complexing agent can form more than one bond with polyvalent
ion, then it is considered as polydentate and called as chelating agent.
The difference between sequestering agent and chelating agent is that
the sequestering agent remains in the solution in the chelated
condition where as chelating agent forms an insoluble complex with
the metal ion.
In all EDTA Complexometric reactions the ratio of EDTA to the
metal ion is 1:1
E.g.; dimethylglyoxime and salicylaldoxime are e.g. for chelating
agent where as EDTA is an e.g. for sequestering agent.
12. 12
Direct titration
A standard solution is added directly to the solution of the
substance being determined are referred to as a direct titration.
The solution containing the metal ion to be determined is
buffered to the desired pH and few drops of indicator is added.
The contents are titrated against standardized disodium edetate
solution till the end point shown by the colour change.
A blank titration is carried out omitting the substance to be
determined, but contains all the other solutions like buffer &
indicator.
The volume of edetate consumed in blank titration is substracted
from that obtained in the original estimation
Examples of such estimation:
Bismuth - Nitrate, carbonate, oxynitrate, sub nitrate
Calcium - Chloride, gluconate, lactate, carbonate,
Magnesium - Carbonate, oxide, stearate, sulphate,
13. 13
1. Assay of magnesium sulphate
Principle:
Magnesium sulphate forms stable complex with disodium edetate in presence of
strong ammonia-ammonium chloride buffer.
It is assayed by direct titration method.
Mordant black mixture is used as indicator for detection of end point {red to blue}
and standard 0.05 M disodium edetate is employed as titrant.
Mg2+ + EDTA → Mg EDTA
Materials required:
Standard disodium edetate 0.05 M, Magnesium sulphate sample (0.4 g),
Ammonia-ammonium chloride buffer (10ml), Mordant black mixture as indicator.
14. Preparation of reagents
0.05M Disodium EDTA – 18.6g EDTA Disodium is
added to AR grade water to produce 1000ml.
Ammonia-ammonium chloride buffer solution- dissolve
67.5g of ammonium chloride in 650ml of AR grade water
and add strong ammonia solution .Make up the volume to
1000ml with AR grade water.
If it is MgSO4 7H20-0.4g OR 0.3g of anhydrous
magnesium sulphate.
15. 15
Assay:
Weigh accurately about 0.3 g anhydrous magnesium sulphate
,transfer into 250ml conical flask and dissolve in 50 ml of
water. Add 10 ml of strong ammonia-ammonium chloride
solution, and titrate with 0.05M disodium
ethylenediaminetetraacetate using 0.1 g of mordant black II
mixture as indicator, until the pink colour is discharged from
the blue.
Equivalent factor:
0.006019g Mg SO4 ≡ 1 ml 0.05M disodium EDTA
Percentage purity w/w = 0.006019*volume of Edetate*M of edetate *100
Weight taken * 0.05
16. 16
2. Assay of calcium carbonate:
Principle:
This is based on the principle of complexometric
titration. Disodium edetate is used as sequestering
agent. Dil HCl is used in order to dissolve calcium
carbonate in water because as such it is insoluble in
water.
Acid will generate Co2 which is formed as follows.
2HCl + CaCo3 → CaCl2 + H2CO3
H2CO3 → H2O +CO2
Ca CO3+H20+CO2→ Ca (HCO3)2
Insoluble Soluble
17. 17
PROCEDURE
Weigh accurately about 0.1g and dissolve in 3ml of
dilute hydrochloric acid and 10 ml of water. Boil for
ten minutes, cool, dilute to 50 ml with water. Titrate
with 0.05 M disodium ethylenediamine tetra acetate to
within a few ml of the expected end-point. Add NaOH
and a mixture of calcon and anhydrous sodium
sulphate as indicator and continue the titration until
the colour changes to a full blue colour.
Each ml of 0.05M disodium ethylenediamine tetra
acetate is equivalent to 0.005004 g of CaC03.
18. Back Titration
Is necessary if the analyte precipitates in the absence of
EDTA, if it reacts too slowly with EDTA, or if it blocks the
indicator (i.e. cannot be displaced by EDTA from the
indicator). A known excess of EDTA is added to the analyte
solution; the excess is titrated with a standard solution of
another metal ion, which must not displace analyte from
EDTA (often Mg2+ is used)! Determination of the excess not
required by the sample hence the amount of volumetric
solution used by the substance is determined.
If the analyte precipitates without EDTA, an acidified
solution of analyte (metals in general dissolve better at low
pH) is treated with excess EDTA, then adjusted to the
required higher pH.
19. In general this method is used for :
1.Volatile substances eg: ammonia
2.Insoluble substances eg: calcium carbona
3.Substances which need excess of reagent
eg: lactic acid
19
20. 20
PROCEDURE:
Weigh accurately about 80mg of sample.
To the sample add 45ml of water,0.2g of sodium chloride
and 20ml ethanol.
Heat to boiling and add 0.05M lead nitrate, intially
dropwise and then more rapidly, with constant stirring.
Heat to coagulate the precipitate, cool to room
temperature.
PROCEDURE FOR ASSAY OF ALUM
21. 21
Filter and wash the residue with small
volumes of alcohol.
To the filtrate and washings, add
hexamine(1g) and titrate the excess lead
nitrate with 0.05M disodium edetate using
xylenol orange solution as indicator.
The end point is yellow.
22. Assay of aluminium hydroxide gel
Procedure:
Weigh accurately about 5g of the substance in a 100ml of
conical flask, add 3ml of 6M HCL .
Dissolve the suspension by a slight warming on a water
bath.
Cool to room temperature and transfer to a 100ml
volumetric flask and make up to the mark with water.
22
23. Pipette out 25ml of this solution in to a 250ml conical flask
and add 40ml of the standard 0.05MEDTA solution .
Dilute with 80ml of water and add 2-3 drops of methyl red
indicator
Add 1M NaOH to neutralise the mixture as will be
recognised by change of colour of the indicator from red to
yellow.
This solution is warmed on a water bath for 30mns then add
3g of hexamine and xylenol orange as indicator,the titration
mixture becomes yellow in colour.
23
24. Now the mixture is titrated with a
standard 0.05M lead nitrate solution.
End point is violet colour.
24
25. ASSAY OF Manganese II
Mn II cannot be titrated with EDTA alkaline
solution,owing to precipitation of the manganese
hydroxide .An excess of EDTA is added to an acidic
solution of the manganese salt,an ammonia buffer is
used to adjust the solution PH to 10 and the excess
EDTA remaining after chelation is titrated with a
standard Zn II solution using Erichrome black T as
indicator .
26. Replacement Titration
The method of displacement titration involves the
quantitative displacement of a second metal ( M II)
from a complex by the metal ( M1) being
determined.The freed second metal is then directly
titrated by a standard chelon solution .
27. ASSAY OF CALCIUM GLUCONATE
Calcium gluconate is assayed by complexometric
replacement titration method.In the estimation of
calcium ions,ammonia-ammonium chloride buffer
and a known volume of magnesium sulphate is added
.This forms Mg-EDTA complex.In the reaction a stable
calcium EDTA complex is formed and magnesium ions
are liberated which is titrated with standard disodium
edetate solution.
BLANK-Another titration is carried out with same
quantities of reagent under same condition without
sample(calcium gluconate)
28. b) The difference between (A-B) gives the amount of disodium
edetate consumed by the calcium gluconate.
ca2+ + Mg-EDTA Ca-EDTA+ Mg2+
Mg2+ + EDTA Mg-EDTA
29. 470
Figure 17-6
EDTA titration curves for
50.0 mL of 0.00500 M Ca2+
(K’CaY=1.75×1010) and Mg2+
(K’MgY=1.72×108) at pH 10.0.
Note that because of the larger
formation constant, the
reaction of calcium ion with
EDTA is more complete, and a
larger change occurs in the
equivalence-point region. The
shaded areas show the
transition range for the
indicator Eriochrome Black T.
30. PROCEDURE
Transfer an accurately weighed quantity of about 0.5g
of calcium gluconate to a 250ml conical flask ,add 50ml
of water to dissolve it.
Add 5ml of magnesium sulphate (0.5M) and 10ml strong
ammonia-ammonium chloride solution and titrate the
mixture with the 0.5M disodium edetate solution using
mordant black mixture as indicator to blue colour.Note the
reading as A.
Repeat the experiment with the same reagents except
sample.Blank reading B.
31. The difference between (A-B) gives the amount of disodium
edetate required by the sample.
Each ml of 0.5M disodium edetate = 0.02242g of
calcium gluconate.
Percentage w/w=
---
Volume of EDTA required (A-B)* M of EDTA *0.002242*100
Weight of sample* 0.05
32. PM INDICATORS
The indicators used in Complexometric titrations are called as
pM indicators, since these indicators are responsive to the
concentration of the metal ions in solution.
pM indicators are chelating agents which give specific colour on
the formation of complex with metal ions.
The free chelate and the complex with metal ions have two
different colours.
Hence based upon the concentration of the metal ion, the colour
of the indicator changes and so the end point of such titration
can be known.
pM is the negative logarithm of metal ion
concentration.
pM = -log [M]
34. DESCRIPTION
This is the ammonium salt of purpuric acid, and its anion has the structure.
It was the first metal ion indicator to be employed in the EDT A titration.
Murexide solutions are reddish-violet up to pH = 9 (H4D-),
Violet from pH 9 to pH 11 (H3D2 -), and
Blue-violet (or blue) above pH 11(H2D3 -).
These colour changes are probably due to the progressive displacement of
protons from the imido groups.
Murexide forms complexes with many metal ions: only those with Cu, Ni, Co,
and the lanthanoids and their colours in alkaline solution are orange (copper),
yellow (nickel and cobalt), and red (calcium); the colours vary somewhat with
the pH of the solution.
Murexide may be employed for the direct EDT A titration of calcium at pH =11,
the colour change at the end point is from red to blue-violet, similarly the
colour change in the direct titration of nickel at pH 10-11 is from yellow to blue-
violet.
35. PREPARATION
Aqueous solutions of Murexide are unstable and must
be prepared each day. The indicator solution may be
prepared by suspending 0.5 g of the powdered dyestuff
in water, shaking thoroughly, and allowing the
undissolved portion to settle. The saturated
supernatant liquid is used for titrations.
37. DESCRIPTION
This substance is sodium 1-(1-hydroxy-2-naphthylazo)-
6-nitro-2-naphthol-4-sulphonate).
In strongly acidic solutions the dye tends to polymerise
to a red-brown product, and therefore the indicator is
rarely applied in the EDT A titration of solutions more
acidic than pH = 6.5.
The sulphonic acid group gives up its proton long
before the pH range of 7-12, which is of more interest
for metal-ion indicator use.
38. CONTINUED……
This colour change can be observed with the ions of Mg, Mn, Zn, Cd,
Hg, Pb, Cu, and the Pt metals.
To maintain the pH constant buffer mixture is added, and to keep the
above metals in solution weak complexing reagent such as ammonia or
tartarate is added.
The cations of Cu, Co, Ni, Al, forms such stable indicator complexes
that the dye can not be liberated by adding EDT A: direct titration of
these ions using Solochrome Black indicator is not possible because
the metallic ions are said to 'block' the indicator.
However, with Cu, Co, Ni, and Al a back-titration can be carried out, by
titrating the excess of EDTA with standard me or magnesium ion
solution.
The indicator solution is prepared by dissolving 0.2 g of the dyestuff in
15 ml of triethanolamine with the addition of 5 ml of absolute ethanol
to reduce the viscosity.
39. Determine the transition ranges for Eriochrome
Black T in titrations of Mg2+ and Ca2+ at pH 10.0,
given that (a) the second acid dissociation
constant for the indicator is
(b) The formation constant for MgIn- is
(c) Ca2+ Kf = 2.5x105
H2O + HIn2
-
In3-
+ H3O+
K2 = 2.8 x 10-12
Mg2+
+ In3-
MgIn-
Kf = 1.0 x 107
41. CONTINUED…..
This is sometimes referred to as Eriochrome Blue Black RC.
It is sodium 1-(2-hydroxy-l-naphthylazo)-2-naphthol-4-
sulphonate.
The dyestuff has, two ionisable phenolic hydrogen atoms; the
protons ionise stepwise with pK’s of 7.4 and 13.5 respectively.
An important application of the indicator is in the
Complexometric titration of calcium in the presence of
magnesium is carried out at a pH of about 12.3 in order to avoid
the interference magnesium.
The magnesium is precipitated quantitatively as the hydroxide.
The colour change is from pink to pure blue.
The indicator solution is prepared by dissolving 0.2 g of the
dyestuff in 50 ml of methanol.
43. CONTINUED…..
This indicator is prepared by the condensation of O-
cresolsulphonephthalein (Cresol Red) with
formaldehyde and iminodiacetic acid.
This is 3 ,3' -bis [N,N -di( carboxymethyl )-amino
methyl ]-o-cresolsulphonephthalein
Special feature is dyestuff retains the acid-base
properties of Cresol Red and displays metal indicator
properties even in acid solution (pH = 3-5).
Acidic solutions of the indicator are coloured lemon-
yellow and those of the metal complexes coloured red.
44. CONTINUED…..
Direct EDTA titrations of Bi, Th, Zn, Cd, Pb, Co, etc.,
are readily carried out and the colour change is sharp.
By appropriate pH adjustment certain pairs of metals
may be titrated successfully in a single sample
solution.
Thus bismuth may be titrated at pH = 1-2 and zinc or
lead after adjustment to pH = 5 by addition of
hexamine.
The indicator solution is prepared by dissolving 0.5 g
of Xylenol Orange in 100 ml of water.
46. CONTINUED….
This indicator, 1-(1-hydroxyl-4-methyl-2-phenylazo)-2-
napthol-4-sulphonic acid, has the same colour change
as Solochrome.
It may be substituted for Solochrome Black without
change in the experimental procedures for the
titration of calcium Plus magnesium.
Calmagite functions as an acid-base indicator.
The hydrogen of the sulphonic acid group plays no
part in the functioning of the dye as a metal ion
indicator.
47. CONTINUED…
The acid properties of the hydroxyl groups are expressed by
pKl = 8.14 and pK2 = 12.35.
The blue colour of Calmagite at pH= 10 is changed to red by
the addition of magnesium ions.
The pH = 10 is attained by the use of an aqueous ammonia-
ammonium chloride buffer mixture.
The indicator solution is prepared by dissolving 0.05 g of
Calmagite in 100 ml of water. It is stable for at least 12
months when stored in a polythene bottle.
50. CONTINUED….
Indicator is blue in colour at pH 10.
On complexation with metal ions pink colour is formed.
Below pH 6.3 and above 11.5 it is reddish in colour hence it
is used at pH 10.
It is used in the estimation of metal ions like Calcium,
Magnesium, Zinc, Cadmium, Lead and Mercury.
It can’t be used with oxidizing ions like ferric, cerric or with
reducing ions like stannous and titannous.
It can’t be used with ions like copper, aluminum, cobalt,
silver as these ions form more stable complexes with
indicator than with chelating agent.
51.
52. 52
APPLICATIONS
Determination of water hardness
Determination of metal ions
Complexometric titrations are widely
used in the medical industry.
The traces of zinc in water can be
determined with complexometric titration
53. •'Soft' water has a hardness < 60 mg CaCO3/L, and can lead to corrosion of
pipes. 'Hard' water has a hardness > 270 mg CaCO3/L, and can lead to
deposition of Ca and Mg minerals (limescale in water heaters, pipes etc.). Ca2+
also precipitates soap: Ca2+ + 2 RCOO- → Ca(OOCR)2 Temporary hardness is
caused by Ca(HCO3)2 and can be removed by boiling:
• CaCO3 ↓ + CO2 ↑ + H2O Ca(HCO3)2 CaCO3
precipitates and the water left is now softer, but CaCO3 has to be removed or
(some of) it will dissolve again.
• Permanent hardness is mainly caused by Ca2+/Mg2+ sulfates and chlorides –
cannot be removed by boiling, but can be removed by ion exchange
(replacement of Ca2+/Mg2+ by Na+). Determination of the hardness of water
involves direct titration with EDTA of Ca2+ and Mg2+ (together) at pH 10
(NH3 buffer). Fe3+ may have to be reduced with ascorbic acid to Fe2+ first, and
then Fe2+ is masked with CN- (which also masks several other minor metal
ions).
54. REFERENCES
Pharmaceutical chemistry theory and application
.Leslie G. Chatten.volume 1
Practical pharmaceutical chemistry by
A.H.Beckett,J.B.Stenlake
Practical pharmaceutical chemistry –I,
A.V.Kasture,S.G.Wododkhar,S.B.Gokhale
54