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.
more chemistry contents are available
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EDTA Titration
content- Principle
Ilkovic equation
Construction and working of dropping mercury electrode and rotating platinum electrode
Applications
Polarography is a voltammetric technique in which chemical species (ions or molecules) undergo oxidation (lose electrons) or reduction (gain electrons) at the surface of a dropping mercury electrode (DME) at an applied potential. Polarography only applies to the DME.
Objective of polarography
Polarography is an electroanalytical technique that measures the current flowing between two electrodes in the solution (in the presence of gradually increasing applied voltage) to determine the concentration of solute and its nature respectively
Polarography is based upon the principle that gradually increasing voltage is applied between two electrodes, one of which is polarisable (dropping mercury electrode) and other is non-polarisable and current flowing between the two electrodes is recorded.
A sigmoid shape current-voltage curve is obtained from which half wave potential as well as diffusion current is calculated.
Diffusion current is used for determination of concentration of substance.
Half wave potential is characteristic of every element.
Ilkovic equation is a relation used in polarography relating the diffusion current (id) and the concentration of the non-polarisable electrode, i.e., the substance reduced or oxidised at the dropping mercury electrode (polarisable electrode).
Definitions of types of currents
1. Residual current (ir), 2. Migration current (im): , 3. Diffusion current (id) 4.Half wave potential 5. Limiting current (il)
Dropping mercury electrode- Dropping mercury electrode (DME) is a polarisable electrode and can act as both anode and cathode.
The pool of mercury acts as counter electrode,
i.e., anode if DME is cathode or
cathode if DME is anode.
The counter electrode is a non-polarisable electrode.
To the analyte solution, electrolyte like KCl is added i.e., 50-100 times of sample concentration.
Pure nitrogen or hydrogen gas is bubbled through the solution, to expel (remove) out oxygen.
Eg: If the analyte solution contains cadmium ions, then cadmium ions are discharged at cathode (-)
Cd2+ + 2e- → Cd
Then, gradually increasing voltage is applied to the polarographic cell and current is recorded.
Graph is plotted between voltage applied and current. This graph is called Polarograph and the apparatus is known as Polarogram.
The diffusion current produced is directly proportional to concentration of analyte and this is used in quantitative analysis.
The half wave potential is characteristic of every compound and this is used in qualitative analysis.
Graph is plotted between voltage applied and current. This graph is called Polarograph and the apparatus is known as Polarogram.
The diffusion current produced is directly proportional to concentration of analyte and this is used in quantitative analysis.
The half wave potential is characteristic of every compound
Learning objectives
Introduction
Preparation of a standard solution used for redox titration
Oxidizing and reducing agents used in volumetric analysis
N/10 potassium permanganate preparation
N/10 potassium dichromate preparation
N/10 Iodine solution preparation
Examples of redox titrations
Conclusion
References
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
content- Principle
Ilkovic equation
Construction and working of dropping mercury electrode and rotating platinum electrode
Applications
Polarography is a voltammetric technique in which chemical species (ions or molecules) undergo oxidation (lose electrons) or reduction (gain electrons) at the surface of a dropping mercury electrode (DME) at an applied potential. Polarography only applies to the DME.
Objective of polarography
Polarography is an electroanalytical technique that measures the current flowing between two electrodes in the solution (in the presence of gradually increasing applied voltage) to determine the concentration of solute and its nature respectively
Polarography is based upon the principle that gradually increasing voltage is applied between two electrodes, one of which is polarisable (dropping mercury electrode) and other is non-polarisable and current flowing between the two electrodes is recorded.
A sigmoid shape current-voltage curve is obtained from which half wave potential as well as diffusion current is calculated.
Diffusion current is used for determination of concentration of substance.
Half wave potential is characteristic of every element.
Ilkovic equation is a relation used in polarography relating the diffusion current (id) and the concentration of the non-polarisable electrode, i.e., the substance reduced or oxidised at the dropping mercury electrode (polarisable electrode).
Definitions of types of currents
1. Residual current (ir), 2. Migration current (im): , 3. Diffusion current (id) 4.Half wave potential 5. Limiting current (il)
Dropping mercury electrode- Dropping mercury electrode (DME) is a polarisable electrode and can act as both anode and cathode.
The pool of mercury acts as counter electrode,
i.e., anode if DME is cathode or
cathode if DME is anode.
The counter electrode is a non-polarisable electrode.
To the analyte solution, electrolyte like KCl is added i.e., 50-100 times of sample concentration.
Pure nitrogen or hydrogen gas is bubbled through the solution, to expel (remove) out oxygen.
Eg: If the analyte solution contains cadmium ions, then cadmium ions are discharged at cathode (-)
Cd2+ + 2e- → Cd
Then, gradually increasing voltage is applied to the polarographic cell and current is recorded.
Graph is plotted between voltage applied and current. This graph is called Polarograph and the apparatus is known as Polarogram.
The diffusion current produced is directly proportional to concentration of analyte and this is used in quantitative analysis.
The half wave potential is characteristic of every compound and this is used in qualitative analysis.
Graph is plotted between voltage applied and current. This graph is called Polarograph and the apparatus is known as Polarogram.
The diffusion current produced is directly proportional to concentration of analyte and this is used in quantitative analysis.
The half wave potential is characteristic of every compound
Learning objectives
Introduction
Preparation of a standard solution used for redox titration
Oxidizing and reducing agents used in volumetric analysis
N/10 potassium permanganate preparation
N/10 potassium dichromate preparation
N/10 Iodine solution preparation
Examples of redox titrations
Conclusion
References
Important Questions For Pharmaceutical Inorganic Chemistry(FAQ)Payaamvohra1
This ppt gives you an idea about FAQ in end semesters of B -pharmacy exams Mostly this ppt covers 85% of your entire syllabus so one can score well Pharmaceutical inorganic chemistry of B Pharmacy 1st semester .Do follow my uploads for important tips tricks hints in pharmacy
This presentation includes the most important cell used in polarography Dropping Mercury Electrode. Its structure, uses/Advantages and limitations are explain here
Polarographic technique is applied for the qualitative or quantitative analysis of electroreducible or oxidisable elements or groups.
It is an electromechanical technique of analyzing solutions that measures the current flowing between two electrodes in the solution as well as the gradually increasing applied voltage to determine respectively the concentration of a solute and its nature.
The principle in polarography is that a gradually increasing negative potential (voltage) is applied between a polarisable and non-polarisable electrode and the corresponding current is recorded.
Polarisable electrode: Dropping Mercury electrode
Non-polarisable electrode: Saturated Calomel electrode
From the current-voltage curve (Sigmoid shape), qualitative and quantitative analysis can be performed. This technique is called as polarography, the instrument used is called as polarograph and the current-voltage curve recorded is called as polarogram
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
Important Questions For Pharmaceutical Inorganic Chemistry(FAQ)Payaamvohra1
This ppt gives you an idea about FAQ in end semesters of B -pharmacy exams Mostly this ppt covers 85% of your entire syllabus so one can score well Pharmaceutical inorganic chemistry of B Pharmacy 1st semester .Do follow my uploads for important tips tricks hints in pharmacy
This presentation includes the most important cell used in polarography Dropping Mercury Electrode. Its structure, uses/Advantages and limitations are explain here
Polarographic technique is applied for the qualitative or quantitative analysis of electroreducible or oxidisable elements or groups.
It is an electromechanical technique of analyzing solutions that measures the current flowing between two electrodes in the solution as well as the gradually increasing applied voltage to determine respectively the concentration of a solute and its nature.
The principle in polarography is that a gradually increasing negative potential (voltage) is applied between a polarisable and non-polarisable electrode and the corresponding current is recorded.
Polarisable electrode: Dropping Mercury electrode
Non-polarisable electrode: Saturated Calomel electrode
From the current-voltage curve (Sigmoid shape), qualitative and quantitative analysis can be performed. This technique is called as polarography, the instrument used is called as polarograph and the current-voltage curve recorded is called as polarogram
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
The pptx on complexometric titrations, EDTA titration, Why EDTA is used in complexometric titration, Classification of EDTA titration, EDTA titration curve etc.
complexometric titration , colorimetry and spectrophotometry ushaSanmugaraj
it consists of notes for complexometric titration principle, edta, procedure, applications. colorimetry and spectrophotometry principle, introduction, instrumentation and applications
Complex-formation reactions are widely used in analytical chemistry. One of the first uses of these reagents was for titrating cations. In addition, many complexes are colored or absorb ultraviolet radiation; the formation of these complexes is often the basis for spectrophotometric determinations. Some complexes are sparingly soluble and can be used in gravimetric analysis. Complexes are also widely used for extracting cations from one solvent to another and for dissolving insoluble precipitates. The most useful complex forming reagents are organic compounds that contain several electron donor groups that form multiple covalent bonds with metal ions.
FORMING COMPLEXES
Most metal ions react with electron-pair donors to form coordination compounds or complexes. The donor species, or ligand is an ion or a molecule that forms a covalent bond with a cation or a neutral metal atom by donating a pair of electrons that are then shared by the two.
The number of covalent bonds that a cation tends to form with electron donors is its coordination number. Typical values for coordination numbers are two, four, and six. The species formed as a result of coordination can be electrically positive, neutral, or negative.
A ligand that has a single donor group, such as ammonia, is called unidentate(single-toothed), whereas one such as glycine, which has two groups available for covalent bonding, is called bidenate. Tridentate, tetradentate, pentadentate, and hexadentate chelating agents are also known.
Another important type of complex, a macrocycle, is formed between a metal ion and a cyclic organic compound. The selectivity of a ligand for one metal ion over another relates to the stability of the complexes formed. The higher the formation constant of a metal-ligand complex, the better the selectivity of the ligand for the metal relative to similar complexes formed with other metals.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
2. Complexometric:
The techniqueinvolves titratingmetal ions with
a complexing or a chelating agent is more
commonly referred to as a complexometric
titration.
Complexation is an acid base reaction between
the ligand, a Lewis base or electron donorand
the metal ion, a Lewis acid or electron acceptor.
The nature of chemical bond between the metal
ion and ligands may vary from covalent or ionic.
3. Applications of complexometric titration:
The Applications of Complexometric Titrations are as follows:
1. Direct Titration: It is the simplest and the most convenient method in
which the standard solution of EDTA is slowly added to the metal ion
solution till the end point is achieved.
It is similar to simple acid-base titrations. For this method to be useful
the formation constant must be large and the indicator must provide a
very distinct color change as mentioned earlier. Further we need
standardized solution of EDTA and sometimes auxiliary complexing
agents may be required.
Some important elements which could be determined directly by the
complexometric titration are Cu, Mn, Ca, Ba, Br, Zn, Cd, Hg, Al, Sn,
Pb, Bi, Cr, Mo, Fe, Co, Ni, and Pd, etc. However, the presence of other
ions may cause interference and need to be suitably handled.
2. Back Titration: In this method, an excess of a standard solution of
EDTA is added to the metal solution being determined so as to complex
all the metal ions present in the solution.
The excess of EDTA left after the complex formation with the metal is
back titrated with a standard solution of a second metal ion.
This method becomes necessary if the analyte precipitates in the absence
4. of EDTA or reacts too slowly with EDTA, or it blocks the indicator. For
example, determination of Mn is done by this method because a direct
titration is not possible due to precipitation of Mn (OH)2. The excess
EDTA remaining after complexation, is back titrated with a standard Zn
solution using Eriochrome black T as indicator. However, one has to ensure the
standard metal ion should not displace the analyte ion from their EDTA complex.
3. Replacement Titration: When direct or back titrations do not give
sharp end points or when there is no suitable indicator for the analyte the
metal may be determined by this method. The metal to be analyzed is
added to a metal-EDTA complex.
The analyte ion (with higher Kf′) displaces EDTA from the metal and
the metal is subsequently titrated with standard EDTA.
For example, in the determination of Mn an excess of Mg EDTA
chelate is added to Mn solution.
The Mn ions quantitatively displace Mg from Mg-EDTA solution
because Mn forms a more stable complex with EDTA.
Mn+ + MgY2 - (MY)(n - 4)+ + Mg2+
The freed Mg metal is then directly titrated with a standard solution of
EDTA using Eriochrome black T indicator. Ca, Pb and Hg may also be
determined by this method.
5. 4. Indirect Titration: Certain anions that form precipitate with metal
cations and do not react with EDTA can be analyzed indirectly. The
anion is first precipitated with a metal cation and the precipitate is
washed and boiled with an excess of disodium EDTA solution to form
the metal complex.
Mn+ + H2Y2 - (MY)(n - 4)+ + 2H+
The protons from disodium EDTA are displaced by a heavy metal and
titrated with sodium alkali. Therefore, this method is also called
alkalimetric titration.
For example, barbiturates can be determined by this method.
Aquametric:
Aquametry is a quantitative method of determining water content
present in a sample. Determination of water is one of the most important
and widely practiced analytical methods in pharmaceutical industry.
6. Applications of aquametric titration:
The Applications of aquametric Titrations are as follows:
Soil quality: The appearance of large information banks on soil
properties in Europe was provoked by necessity of increasing of
agricultural production economics, i.e. the commercial price of soil as
the production medium. Quality of food materials and products:
Moisture content affects food quality, i.e. texture, taste, appearance and
stability of foods depends on the amount of water they contain. A
knowledge of the moisture content is often necessary to predict the
behavior of foods during processing, e.g. mixing,drying, transportation,
flow through a pipe or packaging, storage stability or shelf-life
Environmental monitoring: The need for monitoring physical
conditions in agriculture and environment is increasing because of
increasing pressure on natural resources, sustainability, exhaustion of
nonrenewable resources and climate change.
7. Amperometry:
Amperometry is also one of this technique which require complicated
and expensive specialized equipment handled by a qualified personnel
and are usually labour- and time-consuming. But at the same time this
technique gives accurate results with many additional updates.
Applications Of Amperometric Titrations
Amperometric titrations have even huger range of applications than
polarography since even electro-inactive substances could be determined
using electro-active titrant.
According to Ilkovic equation id is proportional to concentration keeping
all other factors of the equation constant. Then, if a few of the
electroactive material in the solution is removed through interaction
along with some other reagent (e.g.: EDTA reagent for Zn2+
determination) the diffusion current will decrease. This is the
fundamental principle of polarographic titrations or amperometric
titrations.
8. The diffusion current at a suitable applied voltage is measured as a
function of the volume of the titrating solution. The last point is the
intersection of two lines giving the change of current before and after the
equivalence point.
Table: Examples of amperometric titrations