# chemiologist > Your Gateway to the World of Chemistry ## Posts - [Chemistry of Reversible Reactions and their Industrial Application](https://chemiologist.com/chemistry-of-reversible-reactions-and-their-industrial-application/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Reversible Reactions: All reactions are not reversible. The reactions that are reversible can be stated as: Definition: “The chemical reactions that can go forward as well as backward under the same conditions” are called reversible reactions. The reactants form products, is forward going direction; while the products start forming on reverse the reactants, is backward going direction. Such type of chemical equation is expressed by having double arrow in-between reactants and products. Changing the Condition Can Change Direction: Reversible reactions are bi-directional. This […] - [Physical Versus Chemical Changes & Rate of the Reactions](https://chemiologist.com/physical-chemical-changes-rate-of-the-reactions/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Physical Change: Definition: “The change in the substance in its appearance, shape and size without change in chemical composition and without formation of a new product is called physical change”. For example, water appears in three states (phases), solid in the form of ice, liquid, and gas in the form of steam, and water vapours. The composition remains H2O in all, but the appearances, shapes and sizes are different. The phase change needs change in heat energy. The ice needs heat to melt […] - [Chemical Energetics](https://chemiologist.com/chemical-energetics/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Chemical Energetics: Definition: It can be defined as, “the branch of chemistry that deals with the energy changes during physical or chemical changes”. Types of Energy Changes: There are two types of energy changes, exothermic and endothermic. 1. Exothermic Reactions: The chemical reactions in which the energy is released are called exothermic. Exo means ‘outward’; and thermic has its Greek origin from the word ‘thermos’ meanings ‘heat’. Enthalpy is another synonym of heat having its Greek origin from the word ‘enthalpein’ meaning ‘heating’. […] - [Hydrogen-oxygen Fuel Cells](https://chemiologist.com/hydrogen-oxygen-fuel-cells/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Hydrogen-oxygen Fuel Cell: Definition: It can be defined as, “the electrochemical cell that produces electrical energy by using hydrogen gas as fuel and oxygen gas as oxidant; water is the byproduct by this chemical change”. The fuel cell was invented by a Briton scientist and judge Sir William Robert Grove (1811-1896) in 1838. Components of the Cell: Followings are the major components of the cell: Working of the Cell: Disadvantages of Fuel Cells: Advantages of Fuel Cells: - [Electrolysis and Electroplating](https://chemiologist.com/electrolysis-and-electroplating/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Electrolysis: Definition: It can be defined as, “the chemical decomposition of ionic compounds by passing an electric current from their liquid state or aqueous solution to form new products”. For example: Apparatus for Electrolysis: In a more general form, the apparatus for electrolysis is consisted of the following component parts: Electrolytes: These can be defined as, “the substances, in either molten or aqueous solution state, allow electric current to pass through them and split into ions to bring about chemical changes to form […] - [Titration Technique in Chemistry](https://chemiologist.com/titration-technique-in-chemistry/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Titration (Volumetric Analysis): By definition,“the titration is a lab technique that is used to find out concentration of the substance in the solution”. Titration also known as ‘volumetric analysis’. The origin of the term ‘titration’ is from the old English ‘titre’ meaning ‘concentration of the substance’. The word ‘concentration’ means ‘the amount of the substance dissolved in a given volume of the solution’. Higher the amount, higher will be concentration. Procedure of Titration: Although, there are various types of titrations, but the main […] - [From Empirical to Molecular Formula: Core Concept of Calculations from Experimental Data](https://chemiologist.com/from-empirical-to-molecular-formula-core-concept-of-calculations-from-experimental-data/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Empirical Formula: By definition, “the simple whole number ratio between atoms or ions in a molecule” is called an empirical formula. The whole number means, 1, 2, 3, 4 ……; while the fractions like 0.25, 0.5, or 0.75 …. are not used. The origin of the term is Greek from the word ‘empeiria’ meaning ‘experience, observation, experiment’. Thus, empirical means ‘based upon the data collected by means of empeiria’. The empirical formula is derived by the experimental data in chemistry laboratory. This is […] - [Quantities in Chemistry: Measurements and Relationships](https://chemiologist.com/quantities-in-chemistry-measurements-and-relationships/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Avogadro Number or Constant (NA): Definition: “The number of particles of a substance present in its one mole equals to 6.022×1023”, is called Avogadro number or constant.  Particles mean atoms, ions, molecules (covalent compounds) or formula unit (ionic compounds). Imagine what a great number of particles by 1 mole. The number of particles in one mole of any substance is the same, but the weight in grams is different, as shown in the following table: The quantity of the particles is directly related […] - [Relative and Average Masses: Core Concept Related to Atoms and Molecules](https://chemiologist.com/relative-and-average-masses-core-concept-related-to-atoms-and-molecules/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Relative Atomic Mass (Ar): Definition: “The masses of atoms are compared with the mass of carbon-12”, are called relative atomic masses. Carbon-12 isotope is considered the standard reference to compare atomic masses of the atoms either lighter or heavier. C-12 contains 6 protons plus 6 neutrons in its nucleus. So, it defines the term ‘atomic mass unit’ (amu). One amu equals to 1/12th of C-12. In other words, one amu equals to the mass of a proton or neutron, i.e., 1.67×10-27kg. The formula […] - [From Symbols to Equations: The Basics of Chemistry](https://chemiologist.com/from-symbols-to-equations-the-basics-of-chemistry/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Symbols of Elements Definition: “The short-form of writing the elements is called symbols of elements”. There are different but fixed forms to express elements by the symbols; these are by using: Following tables help to know the symbols of various elements. Go through, how these were formed by using their names, either English or Latin/Greek. Compounds and Their Formulae: By definition, “the compounds are pure substances that are formed by chemical combination between atoms either similar or dissimilar”.  The term ‘formula’ is singular; […] - [Metallic Bond and Properties of Metals](https://chemiologist.com/metallic-bond-and-properties-of-metals/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Metallic Bond: Definition: “The type of chemical bond in metals where the valence electrons are delocalized to move freely between cationic atoms; resultantly electrostatic attractive forces are created between oppositely charged particles”. Electronic Cloud: The sea of electrons is another term used for electronic cloud. The electrons of the outermost shells are called valence electrons. These establish a loose bonding and do not stay in their own shells but escape. So, an electronic cloud is formed by these delocalized electrons. Resultantly, neutral atoms […] - [Giant Covalent Structures](https://chemiologist.com/giant-covalent-structures/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Diamond : A macromolecule The diamond is a giant (big) covalent molecule having only carbon atoms; also categorized as macromolecule. Each carbon atom needs four electrons more to complete its outermost shell by pairing up; and they do so by mutual sharing. The carbon atom has the geometry of tetrahedron (four sided). In three-dimensional space, it has four orientations and each contains unpaired (1 = single) electron. Thus, each carbon atom links with four carbons for pairing up of electrons by mutual sharing […] - [Properties of Simple Covalent Compounds](https://chemiologist.com/properties-of-simple-covalent-compounds/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Melting & Boiling Points: The simple covalent molecules have very low melting and boiling points. There are two types of forces in the compounds: Intermolecular forces are always weak as compared to intra-molecular. In simple covalent molecules these are much weaker; so, causing the melting and boiling points lower. Intermolecular forces are shown always by dotted lines. Following diagram shows the forces between and within molecules of water. In water, the intermolecular forces exist between oxygen of one molecule and the hydrogen of […] - [Simple Covalent Molecules](https://chemiologist.com/simple-covalent-molecules/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Covalent Bond: Definition: “The type of chemical bond that is formed by mutual sharing of electrons between atoms”. This type of chemical bonding was proposed by an American chemistry professor Gilbert Newton Lewis (1875-1946) in 1916. He described the structures by dots called “Lewis Dot Structures”; as described below in the section of ‘electrons of OMS’. Features: Electrons in OMS: There might be two types of electrons in outermost shell, these are the following 1 & 2 (before sharing); and 1 & 3 […] - [Properties of Ionic Compounds](https://chemiologist.com/properties-of-ionic-compounds/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Crystal Lattice : Definition: “The particles of crystalline solids exist in symmetrical arrangement of three-dimensional repeating pattern called crystal lattice”. Lattice means a ‘grid’. NaCl Crystal Lattice and Unit Cell: Sodium chloride occurs naturally as ‘rock salt’, also known as ‘halite ore’, as shown in picture below. It is a crystalline solid and exists as ‘cube’ by the arrangement of particles. There is an alternative arrangement of Na+ and Cl– ions in the cube. A unit cell can be defined as “the smallest […] - [Understanding Ionic Bonding Through Common Examples](https://chemiologist.com/understanding-ionic-bonding-through-common-examples/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Ionic Bond: Definition Cluster of Ions: Ionic bond also known as “electrovalent bond”. The electrostatic attractions between oppositely charged ions make a cluster of cations and anions, as shown in the following diagram. Exercise 1: From the following three-dimensional structure, point out the mistakes created at two places. Simple Whole Number Ratio: Although, ionic bonds are cluster of ions but their formula is a simple whole number ratio. For example, NaCl, KCl, CaBr2, FeCl3, K2O etc. To understand the concept, look at tiles […] - [Understanding Ions and their Formation](https://chemiologist.com/understanding-ions-and-their-formation/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents:                                                                                                       What are Ions? By definition,“when neutral atoms change their electronic configuration by gaining or losing electrons from their outermost shell, then ions are formed”. The outermost shell also called valence shell, last shell or highest energy shell. Oxidation State: “The charge carried by an ion” is called oxidation state or oxidation number. For example, Ca2+, Cl–, 2+ and -1 are oxidation states of calcium and chlorine respectively. Types of Ions: There are two types of ions that are formed: The cation formation can […] - [Isotopes](https://chemiologist.com/isotopes/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Definitions of Isotopes:   Etymology: Origin of the term‘isotope’ is Greek ‘isos’ plus ‘topos’; meanings ‘same or equal’ and ‘place’ respectively. So, isotope means ‘the same place’. All isotopes of an element given the same place (box) in the periodic table. Because, modern periodic table is based upon ‘atomic numbers’, rather than ‘atomic mass’. And according to definition, isotopes of the same element don’t differ from one another with respect to atomic number. All the isotopes of hydrogen are considered to be placed […] - [Groups & Periods of Periodic Table](https://chemiologist.com/groups-periods-of-periodic-table/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Groups’ Numbers and Names: 1A: H, Li, Na, K, and others carry 1 electron in OMS, and belongs to 1A. 2A: Be, Mg, Ca, and others carry 2 electrons in OMS, and belongs to 2A. 3A: B, Al and others carry 3 electrons in OMS, and belongs to 3A. 4A: C, Si and others carry 4 electrons in OMS, and belongs to 4A. 5A: N, P and others carry 5 electrons in OMS, and belongs to 5A. 6A: O, S and others carry […] - [Electronic Configuration of Noble Gases](https://chemiologist.com/electronic-configuration-of-noble-gases/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Noble Gases and their Position in Periodic Table: Helium, neon, argon, krypton, xenon, radon & oganesson are seven known noble gases and aka inert gases. These are placed at extremely right column (18th) of Moseley Modern periodic table, https://chemiologist.com/atomic-number-and-its-use-in-periodic-table/ . In other words, each period of the periodic table ends at a particular noble gas as shown below. A summary of the noble gases is shown in the following diagram of periodic table. Each period starts from left side and ends at right […] - [Electronic Configuration of Shells K, L, M, N](https://chemiologist.com/electronic-configuration-of-shells-k-l-m-n/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Contents: Shells or Orbits: The shell is recognized as energy level around the nucleus of an atom where electrons revolve. There are different energy levels, seven, around the nucleus, recognized as K, L, M, N, O, P & yet finally the Q. The orbits are the imaginary circular paths where electrons revolve. A shell is the energy level of an orbit. An orbit is also recognized as K, L, M, N, O, P, and yet finally the Q with respect to their energy levels. […] - [Neutrons Atomic Mass & Mendeleev Periodic Table : Foundational Principles](https://chemiologist.com/neutrons-atomic-mass-mendeleev-periodic-table-foundational-principles/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Atomic Mass By a more comprehensive definition, “the atomic mass is the sum of relative masses of all the subatomic particles in an atom”. It will give the same calculation results as the above one. For example, the lithium has 4 neutrons, 3 protons and 3 electrons. The relative mass of neutron is 1, the relative mass of proton is also 1, while the relative mass of electron is zero. So, it will calculate 7 the atomic mass by […] - [Atomic Number and its Use in Periodic Table](https://chemiologist.com/atomic-number-and-its-use-in-periodic-table/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Atomic Number and Periodic Table By definition, “the number of protons of an atom of an element is called atomic number”. The atomic number is written by a symbol ‘Z’; and aka Proton Number. Different elements are different from each other due to having differences in the number (quantity) of their subatomic particles: protons, electrons and neutrons. The main identity of an atom is its atomic number; in other words, counting the number of protons that exist in a […] - [Atomic Structure: Some Basic Facts](https://chemiologist.com/atomic-structure-some-basic-facts/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition of an Atom By definition, “an atom is a smallest yet invisible unit of an element that can undergo into chemical reactions and is consisted of subatomic particles”. Subatomic Particles: An atom is consisted of mainly three subatomic particles, these are: Nucleus & Shells: The atomic structure is consisted of two parts, nucleus and the shells, the locations of subatomic particles. Nucleus is a central (inner) part of the atom and is consisted of neutrons and protons. The […] - [Elements, Atoms, Compounds, Molecules and Mixtures](https://chemiologist.com/elements-atoms-compounds-molecules-and-mixtures/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Element: Definition and Introduction By definition, “an element is a substance made by identical particles”. These particles are called atoms. Different elements have different atoms which are not identical by their structure. For example, iron is an element and all atoms are identical. Gold is another element and its identical atoms are different from iron. There are total 118 different elements that have been arranged in a periodic table in a particular way; out of which 92 are naturally […] - [Rate of Diffusion & Molecular Mass](https://chemiologist.com/rate-of-diffusion-molecular-mass/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Rate of Diffusion and Molecular Mass: The diffusion in gases is at higher rate as compared to liquids and solids. However, different gases have different rates of diffusion. This rate (speed) depends upon molecular masses of the gases. Higher the molecular mass of a gas, slow will be its rate to diffuse; and vice versa. Experimental Verification: Take a long glass tube, plug it’s both ends with cotton soaked in concentrated solutions of hydrochloric acid and ammonia. At one […] - [Experimental Verification's of Diffusion](https://chemiologist.com/experimental-verifications-of-diffusion/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: For detailed conceptual understanding of diffusion, click on the link: https:/diffusion-and-kinetic-particle-theory/ Experimental Verification 1: Diffusion between Hydrogen Gas & Air Following experiment provides evidence related to diffusion between hydrogen gas and the air.  Apparatus Setting: Experiment: Observations: Experimental Verification 2: Diffusion between Carbondioxide & Air Following experiment provides evidence related to diffusion between carbondioxide gas and air.  Apparatus Setting: Almost same as in experiment 2 with slight differences. Get the concept by the following diagram. Experiment: Now, fill a […] - [Diffusion and Kinetic Particle Theory](https://chemiologist.com/diffusion-and-kinetic-particle-theory/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Diffusion: Introduction & Definition: The Latin word ‘diffundere’ is a root of the term ‘diffusion. The meaning of the diffundere is ‘to spread out, to disperse, to scatter’. We can smell the perfume from the distance because, its particles permeate in the air. By definition the diffusion can be defined as, “the spreading of the particles of matter towards the area of lower concentration from the area where their concentration is higher by means of kinetic energy and the […] - [Effects of Temperature & Pressure on Gas Volume: An Explanation by KPT](https://chemiologist.com/effects-of-temperature-pressure-on-gas-volume-an-explanation-by-kpt/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Kinetic Particle Theory of Gases: Postulates This theory has the following postulates related to gases. Temperature & Volume of Gas: Relationship By a simple definition, “the volume of a gas has a direct relationship with temperature at constant pressure”. Mathematically, it would be expressed as: The ‘α – alpha’ is a Greek alphabet that is used as a symbol to show relationship between two variables (here, V & T). This relationship was formulated by Jacques Alexandre Cesar Charles (1746-1823) […] - [Heating & Cooling Curves of Water](https://chemiologist.com/heating-cooling-curves-of-water/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Phase Changes:             This article describes heating and cooling curves based upon water at 1 atmospheric pressure (sea level). The link https:/change-of-state-of-matter/ describes what is phase and its change. Further, melting point, freezing point, boiling point and condensation points have been explained on this link. When a substance changes its appearance (phase) it needs or releases energy in the form of heat. By this, there are two types of curves formed, heating and cooling curves. Heating Curve: Following table […] - [Evaporation and Condensation](https://chemiologist.com/evaporation-condensation/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Evaporation – Definition: The etymology of this term is Latin ‘evaporare’ meaning ‘to disappear in the form of vapours’. So, this term is defined as, “the phenomenon by which liquid disappears in the form of vapours below its boiling point”. Examples: Characteristics of Evaporation: Evaporation & Condensation in Climate:             Water molecules escape from the surface of the water bodies of the earth due to heat by the sun. The water vapours form humidity in the atmosphere. They go up and form […] - [Change of State of Matter](https://chemiologist.com/change-of-state-of-matter/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Three States of Matter: There are three states of matter, solid, liquid and gas; although, the plasma is also considered its fourth state. Here, in this article, the interconversion of three primary states of the matter will be discussed. Kinetic Particle Theory (Kinetic Theory of Matter): This theory describes how the kinetic energy of the matter (particles) is involved to change the state of the matter. The change of the state of matter is called phase change and it is a physical […] - [Particles Separation Arrangement & Motion](https://chemiologist.com/particle-separation-arrangement-motion/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Why Kinetic Particle Theory? Kinetic particle theory (KPT) is a model that explains movements of particles in different states of the matter. KPT aka Kinetic Theory of Matter (KTM). The term ‘kinetic’ has its root from Greek word ‘kinein’ meaning ‘to move’. Definition of KPT: This theory deals with the physical properties of the matter related to arrangement and motion of the particles. The three states of the matter have their distinguished characteristics related to separation, arrangement and the motion of the […] - [Properties of Solids Liquids and Gases](https://chemiologist.com/properties-of-solids-liquids-and-gases/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Matter: Anything that covers space due to its existence and has its mass. Mass is the quantity (amount) of the matter, e.g., 250 grams apples, 1-kilogram potatoes etc. Properties of the Matter – Definition: The characteristics that can be observed and measured are called properties of the matter. These can be chemical as well as physical. Solids, liquids and gases are three states of the matter and have their distinguished properties. Properties of Solids: Properties of Liquids: Properties of Gases: - [Wittig Reaction: Synthesis of Alkene with Ylide](https://chemiologist.com/wittig-reaction-synthesis-of-alkene-with-ylide/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition:             It is a condensation reaction between aldehyde or ketone with triphenylphosphonium ylide to yield triphenylphosphine oxide and alkene. Introduction of Ylide:             This reaction was developed by a German Chemist George Wittig (1897-1987); who was awarded Nobel prize in chemistry in 1979 for his discovery.             Ylide are the organic compounds having positive as well as negative charges, making the molecule overall neutral; in other words, these are dipolar neutral molecules. Ylide etymology is a combination of -yl and -ide. […] - [Stobbes Condensation Reaction](https://chemiologist.com/stobbes-condensation-reaction/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Govt. of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition and Synthesis:             It is a condensation between aldehyde or ketone and the ester of succinic acid to produce alkylidene succinic acid. This reaction was developed by a German chemist Hans Stobbe (1860-1938). Alkylidene Introduction:             When two hydrogen atoms are removed from the same carbon atom of alkane to produce a divalent functional group is called alkylidene radical group of organic compounds; that then makes a double bond with another molecule, as in the example of alkylidene succinic acid. […] - [Reformatsky Condensation Reaction](https://chemiologist.com/reformatsky-condensation-reaction-synthesis-of-s-hydroxyester/): Synthesis of ß-Hydroxyester Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition and Overall Reaction:             Reformatsky Condensation Reaction was developed by a Russian chemist Sergey Nikolaevich Reformatskii (1860-1934). It is a condensation between aldehyde or ketone and alpha-bromoester to produce beta-hydroxyester in acidic media in the presence of zinc. Mechanism: - [Perkin Condensation: Synthesis of Cinnamic Acid](https://chemiologist.com/perkin-condensation-synthesis-of-cinnamic-acid/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Introduction: Cinnamic acid is an organic compound exists naturally in cinnamon (dar-cheeni in Urdu, Hindi). In lab, this compound was synthesized by an English chemist William Henry Perkin (1838-1907). Cinnamic acid has its chemical formula C9H8O2. The crystalline structure has its white powdered appearance with m.pt. 133°C & b.pt. 300°C; the solubility in water is 50mg/100ml. By its structural formula, it is a benzene ring having acrylic acid; so, it is 3-Phenylacrylic acid. Synthesis: In the presence of a base, benzaldehyde […] - [Mannich Condensation Reaction for the Synthesis of beta-Amino-carbonyl Compound: A Mannich Base](https://chemiologist.com/mannich-condensation-reaction-for-the-synthesis-of-beta-amino-carbonyl-compound-a-mannich-base/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Introduction: Beta-amino-carbonyl is a Mannich base that was developed by a German pharmaceutical chemist Carl Ulrich Franz Mannich (1877-1947). The nitrogen atom, in structural formula, is attached with beta-carbon of the compound as shown in the following structure. Synthesis: Mannich reaction is a condensation reaction between aldehyde or ketone and ammonia or primary or secondary amine to form beta-amino-carbonyl compound. The partial negative alpha-carbon of aldehyde or ketone, the partial positive carbonyl-carbon of another aldehyde or ketone, and the nitrogen of […] - [Darzens Glycidic Ester Synthesis](https://chemiologist.com/darzens-glycidic-ester-synthesis/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Introduction: Glycidic ester is an organic compound having two functional groups, epoxide & ester group. In this class of glycidic compounds, not only ester but organic acid group or the hydroxyl groups are also attached with epoxide, forming glycidic acid & glycidol respectively. Synthesis of Glycidic Ester: This ester can be prepared by Darzens condensation reaction. The method was developed by a Russian chemist Auguste Georges Darzens (1867-1954) in 1904. In this reaction, aldehyde or ketone reacts with α-haloester in the […] - [Knoevenagel Condensation Reaction](https://chemiologist.com/knoevenagel-condensation-reaction/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Govt. of the Punjab, Pakistan.The copy of the content is not allowed Contents: Definition: It is a condensation of aldehyde or ketone with an active methylene compound initially in the presence of a base as catalyst, then, forming alpha-beta unsaturation between carbons by dehydration in acidic media.           Modified form of Aldol Condensation:             Knoevenagel reaction is a modified form of aldol condensation, as a double bond is formed between two carbons at the end with the elimination of water molecule. However, in simple aldol, the carbonyl and hydroxyl groups and no unsaturation exist. This […] - [Claisen Schmidt Mechanism Benzylidene Acetone](https://chemiologist.com/claisen-schmidt-mechanism-benzylidene-acetone/): Condensation between Acetone & Benzaldehyde into Benzylidene Acetone Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Content: Definition: The aliphatic aldehydes or ketones show condensation reaction with aromatic aldehydes to yield alpha-beta unsaturated aldehyde or ketone.   Overall Reaction: The mechanism of chemical change takes place in the presence of alkali or an acid. For example, a reaction between an acetone and benzaldehyde. This is solvent free mechanism in the presence of solid NaOH in mortar-pestle and completes in 2-minutes. Resultantly, benzylidene acetone and bis-benzylidene acetone are produced by two […] - [Claisen Condensation Reaction : Mechanism of Chemical Change](https://chemiologist.com/claisen-condensation-reaction-mechanism-of-chemical-change/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition: It is a condensation reaction between two esters to produce beta-diketoester. Chemical Reaction: The condensation between two esters, either similar or dissimilar, were reported for the first time by a German chemist Rainer Ludwig Claisen in 1887. The mechanism is a base catalyzed and the final product is beta-diketoester, also called ß-ketoester. For example, a condensation reaction between methylmethanoate (methylformate) and methylethanoate (methylacetate) can yields beta-diketoester (methyl-3-oxopropanoate) and methanol. Mechanism: The detailed mechanism between ethylethanoate and methylbutanoate is given as […] - [Self-condensation in Ketones](https://chemiologist.com/self-condensation-in-ketones/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Govt. of the Punjab, Pakistan.The copy of the content is not allowed Contents: Introduction: Two ketone molecules show condensation together on the mechanism similar to aldol synthesis. Ketone molecules might be similar or dissimilar. As a result of condensation, the beta-hydroxy ketone is formed. Mechanism of the Synthesis: It is an aldol condensation reaction between two ketones. If these are similar then it would be self-condensation. Like aldol condensation, the presence of alpha-hydrogen is mandatory. The mechanism is either base catalyzed or acid catalyzed. a. Base Catalyzed: The base (OH–) makes water with acidic alpha-hydrogen […] - [Aldol Condensation](https://chemiologist.com/aldol-condensation/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Govt. of the Punjab, Pakistan.The copy of the content is not allowed Contents: Definition: An organic compound containing two functional groups, hydroxyl and aldehyde, is called aldol. The synthesis of aldol by the condensation between aldehydes, aldehyde and ketone and even self-condensation in ketones is called aldol condensation. Etymology of Aldol: As shown in the figure below, an aldol is a combination of ‘ald’ from aldehyde and ‘ol’ from alcohol, because of the presence of two functional groups as stated above. Synthesis: It is a condensation reaction between two aldehydes; these might be similar or […] - [Arylation of Malononitrile with 4-Bromotoluene: Mechanism of Chemical Change](https://chemiologist.com/arylation-of-malononitrile-with-4-bromotoluene-mechanism-of-chemical-change/): Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition: The addition of an aryl group (-Ar) to a methylene group (-CH2-) of an active methylene compound is called arylation. Overall Chemical Reaction: The product is formed by the arylation of malononitrile with 4-bromotoluene by reflux. Tetrahydrofuran is used as solvent; and Palladium complex is used as cross-coupling reagent during the chemical change. Brief Mechanism: The mechanism without considering the involvement of cross-coupling reagent [PdCl2(Ph3P)2] is so simple, as the 4-bromotoluene makes methylphenyl carbocation (p-Tolylcation) by debromination of bromide ion, […] - [Acylation between N-(tert-butoxycarbonyl)-L-phenylalanine and Malononitrile](https://chemiologist.com/acylation-between-n-tert-butoxycarbonyl-l-phenylalanine-and-malononitrile-mechanism-of-chemical-change/): Mechanism of Chemical Change Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition: The addition of an acyl group (RCO-) to methylene (-CH2-) of an active methylene compound is called acylation. Overall Reaction: A general view of acylation reaction is shown as under. N-(tert-butoxycarbonyl)-L-phenylalanine [N-(t-Boc)-L-Pa] is acyl group bearing compound that can undergo into acylation with malononitrile – an active methylene compound. Consequently, a carbon, carbon double bond is formed between two compounds. A detailed mechanism is given here. Mechanism of Chemical Change: A Brief Account of the Chemicals: […] - [Alkylation of 3-Oxobutanenitrile with Methanol](https://chemiologist.com/alkylation-of-3-oxobutanenitrile-with-methanol-mechanism-of-chemical-change/): Mechanism of Chemical Change Dr. Mudassar Altaf, Associate Professor, Department of Higher Education, Government of the Punjab, PakistanThe copy of the content is not allowed Contents: Definition: The addition of an alkyl group (-R) to a methylene group (-CH2-) of an active methylene compound is called alkylation. Overall Reaction: A general mechanism of the chemical reaction is shown here. By means of deprotonation of active methylene compound with the help of a base the alkyl radical (R+) is substituted onto the position of hydron (H+), resultantly, the alkylation occurs. Mechanism of Chemical Change: The comprehensive chemical change has been elucidated here for an […] - [Active Methylene Compounds: An Introduction](https://chemiologist.com/active-methylene-compounds-an-introduction/): Dr. Mudassar Altaf, Associate Professor, Higher Education Department, Government of the Punjab, Pakistan Definition: The organic compounds containing methylene group (-CH2-) that is chemically reactive by containing two acidic hydrogens due to having bonding with two electron withdrawing groups are called active methylene compounds. In the figure, EWG stands for ‘electron withdrawing group’; the central carbon is active methylene containing two acidic H* atoms. Reactivity: The base attacks on acidic hydrogen and creates a negative charge on the carbon atom (carbanion) of methylene by removing H+ ion. The carbanion is a reactive conjugate base and plays its role as active […] - [Titration between HCl and K2CO3](https://chemiologist.com/titration-between-hcl-and-k2co3/): Dr. Mudassar Altaf, Associate Professor of Chemistry The copy of the content is not allowed Paper: P3 Oct./Nov. 2022 9701/36 Question statement: In the experiment, you will determine the concentration of dilute HCl by further diluting it and then titrating with aqueous K2CO3.  Solutions provided:  (a) Method: Shake the volumetric flask and its contents thoroughly. Label this solution FB 4. (b) From your accurate titration results, calculate a suitable mean value to be used in your calculations. Show clearly how you obtained this value. 25.0cm3 of FB 2 required ………………………. cm3 of FB 4.  (c) Calculations: i. Give your answers to c(ii), c(iv) […] - [Methyl Orange Indicator for Titrations](https://chemiologist.com/methyl-orange-indicator-for-titrations/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, PakistanContentsIntroduction Introduction: Methyl orange is an organic compound that is used in acid-base titration. It shows different colours in acidic and basic media; it is yellow in basic but red in acidic medium. This is the reason why methyl orange is used as indicator in volumetric analysis. Physical Properties & Chemical Formula: It is yellow or orange solid and having solubility in water 0.5g/100ml at 20°C. The chemical formula of methyl orange is C14H14N3NaO3S and having molecular mass 327g/mol. The structural formula is not so […] - [Simple Lab Procedures For Extraction Of Analyte From Food Stuff](https://chemiologist.com/simple-lab-procedures-for-extraction-of-analyte-from-food-stuff/): Dr. Mudassar Altaf, Associate Professor of Chemistry, Department of Higher Education, Government of the Punjab, Pakistan Digestion, maceration, infusion, decoction and percolation are usual laboratory techniques for the extraction of active ingredients from the food-stuff. This write-up provides an introduction of these procedures. Contents: Digestion The dried fine particles of food-stuff are soaked in warm water for about few minutes to several hours is called digestion. The boiling water is not used during digestion. The food-stuff is consisted of analyte and the matrix. 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