PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Analytical chemistry → Electroanalytical techniques ↓


Conductometry and potentiometry


In the field of electroanalytical techniques in analytical chemistry, conductometry and potentiometry play important roles. These methods are central to understanding the quantitative aspects of chemical analysis through their unique ways to measure chemical properties.

Conductometry

Conductometry revolves around the measurement of electrical conductivity in a solution. The principle here is that the conductivity of a solution is directly proportional to the concentration of ions present in it. This property makes conductometry a powerful tool for analyzing solutions of electrolytes.

Basic principles

The main principle of conductometry is the measurement of the ability of a solution to conduct electricity. This ability is affected by many factors including the concentration of ions, the mobility of the ions, and the valency of the ionic species. Conductivity (G) is defined as the inverse of resistance (R), measured in siemens (S), and is calculated as:

G = 1/R

Where conductivity is affected by the area of the electrodes and the distance between them, which is described as:

G = k * (A/l)

Where:

  • k is the cell constant
  • A is the area of the electrode
  • l is the distance between the electrodes
Electrode Distance

Application

Conductometry has wide applications in analytical chemistry, including titrations and the evaluation of water purity. In particular, conductometric titrations eliminate the need for indicators that can interfere with the reaction, leading to clear changes in conductivity as the reaction proceeds.

Example: conductometric titration

During a typical conductometric titration, consider the titration of a base with an acid. As the reaction proceeds, hydrogen ions are replaced by hydroxide ions, and the conductivity changes. This provides a visible endpoint when plotted on a graph.

H 3 O + + OH - → 2H 2 O
Volume of base added conductivity

This graph shows the sharp change in conductivity at the end point.

Potentiometry

Potentiometry involves measuring the potential (voltage) of an electrochemical cell. This technique measures the electrical potential difference between two electrodes in solution without drawing any significant current from the cell.

Basic principles

In potentiometry, a specific ion electrode and a reference electrode are used. The potential difference between these electrodes is directly related to the concentration of an analyte in the solution. The fundamental equation governing potentiometry is the Nernst equation:

E = E° + (RT/nF) * ln([Red]/[Ox])

Where:

  • E is the electrode potential
  • E° is the standard electrode potential
  • R is the universal gas constant
  • T is the temperature in Kelvin
  • n is the number of transferred electrons
  • F is the Faraday constant
  • [Red] and [Ox] are the concentrations of the reduced and oxidized species

Application

Potentiometry is widely used in determining the pH of a solution using a pH electrode and in titrations. It provides accurate measurements of ion concentrations in complex matrices without the need for individual calibration against standards for each ion.

Example: pH measurement

A classic example of potentiometry is measuring pH using a glass electrode. This involves measuring the potential difference that develops across a glass membrane when it comes into contact with the test solution.

pH Electrode

The potential difference corresponds to the activity of hydrogen ions, allowing accurate measurement of pH.

Potentiometric titration

Potentiometric titrations involve monitoring the potential of the solution during the titration to detect the end point. Unlike conductometric titrations, they work effectively in turbid and colored solutions, as they are less affected by the presence of particles.

Combination of conductometry and potentiometry

While conductometry and potentiometry are powerful independently, they can also be used together to validate and complement results. A combined approach can establish more reliable endpoints in titrations and analyze complex mixtures with higher accuracy.

Conductometry allows for robust analysis of ionic solubility and precipitation reactions, while potentiometry excels at providing insight into oxidation and reduction reactions. Together, they expand the analytical capability of researchers in studying diverse chemical systems.

Example of integration

Conductometric measurements can provide preliminary information about the progress of a reaction, while potentiometric endpoints confirm the completion of specific steps, such as neutralization or redox potential stabilization in acid–base titrations.

For researchers focusing on electroanalytical techniques, conductometry and potentiometry provide rich data on ion activity and electronegativity that help understand complex biochemical mechanisms and synthesize new compounds with unique electrochemical properties.

In summary, leveraging these methods could transform analytical work, paving the way for advances in environmental testing, pharmaceutical manufacturing, and industrial analysis, and ushering in the next generation of accurate analysis in aqueous systems.


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