Purification of Organic Compounds-Sublimation, Crystallization, Distillation, Fractional Distillation, Vacuum Distillation, Steam Distillation, Differential Extraction, Chromatography

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Organic chemistry was originally limited to the study of molecules created by living organisms, but it has now expanded to encompass man-made substances.

    Methods of Purification of Organic compounds

    Various methods used for the purification of complex organic compounds are discussed below in this article.

    • Sublimation
    • Crystallization
    • Distillation
    • Fractional Distillation
    • Vacuum Distillation
    • Steam Distillation
    • Differential Extraction
    • Chromatography

    Sublimation

    Conversion of a substance from the solid state to the gaseous state without its becoming liquid. An example is a vaporization of frozen carbon dioxide (dry ice) at ordinary atmospheric pressure and temperature.

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Crystallization

    Crystallization is a method used for the purification of substances. The separation technique separates solids from a liquid.

    The process of turning a liquid substance into a highly structured solid whose atoms or molecules are arranged in a well-defined three-dimensional crystal lattice is known as crystallization. A unit cell is a crystal’s tiniest discrete component. There are millions of these unit cells throughout the crystal.

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Distillation

    Distillation is the process of selectively boiling a component in a liquid mixture and then condensing it thereafter. It is a method of separation that can be applied to either get more of one particular component out of a mixture or to separate it out almost completely.

    Fractional Distillation

    Fractional distillation is a type of distillation that involves the separation of miscible liquids. The process involves repeated distillations and condensations and the mixture is usually separated into component parts. The separation happens when the mixture is heated at a certain temperature where fractions of the mixture start to vaporize.

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Vacuum Distillation

    The boiling point depends on atmospheric pressure; if liquids are distilled in an atmosphere with lower pressure, they will boil at a temperature lower than their boiling points. The vacuum pump is used to do this. Reduced air pressure causes liquids to boil more quickly, which speeds up the entire distillation process.

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Steam Distillation

    Steam Distillation is a separation process for temperature-sensitive substances. It is an exclusive kind of distillation. Another option is to separate miscible liquid bases based on how volatile they are. an example would be aromatic compounds. It is essential in some industrialized areas. No chemical reaction occurs in this situation

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Differential Extraction

    Differential extraction is the method of extracting an organic component from its aqueous solution by shaking it with an organic solvent in which it is insoluble.
    As an example, consider the separation of an oil-water mixture.

    Chromatography

    Chromatography is a technique used to separate mixtures. The mixture is passed through another substance, in this case, filter paper. The different colour ink particles travel at different speeds through the filter paper allowing us to see the constituent colours of the pen ink.

    Types of Chromatography

    Chromatography is of two types:

    • Adsorption Chromatography
    • Partition Chromatography

    Adsorption Chromatography

    Adsorption chromatography is a type of chromatography in which the components of a mixture are separated through adsorption.

    Adsorption chromatography is one of the oldest chromatography techniques still in use. It employs a mobile phase, which can be either liquid or gaseous, during the process. During the adsorptive process, the mobile phase is adsorbed onto the surface of a stationary solid phase.

    Adsorption Chromatography is further classified into:

    • Thin Layer Chromatography
    • Column Chromatography

    Thin Layer Chromatography

    Thin-layer chromatography (TLC) separates a mixture of chemicals into their constituents using a glass plate coated with a very thin layer of adsorbent, such as silica gel and alumina, as shown in the image below.

    In this technique, the glass plate is used. The solution of the to-be-separated mixture is applied as a small spot 2 cm above one end of the plate and the plate is placed in a closed jar containing an eluant, which rises up the plate carrying various components of the mixture to various heights.

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Column Chromatography

    Column chromatography, as depicted in the image below, is a technique for separating the components of a mixture using a column of appropriate adsorbent packed in a glass tube. The combination is placed on top of the column, and an adequate eluant is allowed to slowly trickle down the column.

    The separation of the components occurs depending on the degree of adsorption of the components on the wall adsorbent column. The component with the highest absorptivity is kept at the top, while the others flow down to various heights

    Organic chemistry is the study of carbon-containing molecules’ structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur).

    Partition Chromatography

    Partition chromatography refers to the chromatography technique that is based on the partitioning of components of a mixture between stationary and mobile phases. It is classified into several types, including paper chromatography, gas-liquid chromatography, liquid-liquid chromatography, and so on.

    FAQs on Purification of Organic Compound

    Question 1: What is the basic principle of chromatography?

    Answer:

    Chromatography is based on the idea of separating molecules in a mixture that has been added to the ground or solid and liquid stationary states (stable phase) while travelling with the help of a mobile phase. 

    Question 2: What is the Rf value in chromatography?

    Answer:

    In paper chromatography, RF refers to the distance a fluid component goes up a chromatography plate. All chemicals have a common RF value for each solvent, and RF values are used to match unknown samples with known compounds.

    Question 3: What are the four major purifying methods?

    Answer:

    Four major purifying methods are as follows:

    • Filtering
    • Crystalline Formation
    • Sublimation
    • Distillation

    Question 4: How can sublimation be used to purify organic compounds?

    Answer: 

    Sublimation is the process of transforming a solid into a gas without passing through the liquid state. This technique can be used to purify compounds that are sublimable or have vapor pressures that reach atmospheric pressure well before they reach their melting temperatures.

    Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.

    CBSE Class 11 Chemistry Syllabus

    CBSE Class 11 Chemistry Syllabus is a vast which needs a clear understanding of the concepts and topics. Knowing CBSE Class 11 Chemistry syllabus helps students to understand the course structure of Chemistry.

    Unit-wise CBSE Class 11 Syllabus for Chemistry

    Below is a list of detailed information on each unit for Class 11 Students.

    UNIT I – Some Basic Concepts of Chemistry

    General Introduction: Importance and scope of Chemistry.

    Nature of matter, laws of chemical combination, Dalton’s atomic theory: concept of elements,
    atoms and molecules.

    Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry and calculations based on stoichiometry.

    UNIT II – Structure of Atom

    Discovery of Electron, Proton and Neutron, atomic number, isotopes and isobars. Thomson’s model and its limitations. Rutherford’s model and its limitations, Bohr’s model and its limitations, concept of shells and subshells, dual nature of matter and light, de Broglie’s relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers, shapes of s, p and d orbitals, rules for filling electrons in orbitals – Aufbau principle, Pauli’s exclusion principle and Hund’s rule, electronic configuration of atoms, stability of half-filled and completely filled orbitals.

    UNIT III – Classification of Elements and Periodicity in Properties

    Significance of classification, brief history of the development of periodic table, modern periodic law and the present form of periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionization enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater than 100.

    UNIT IV – Chemical Bonding and Molecular Structure

    Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond, covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory, concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of homonuclear diatomic molecules(qualitative idea only), Hydrogen bond.

    UNIT V – Chemical Thermodynamics

    Concepts of System and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state functions. First law of thermodynamics – internal energy and enthalpy, measurement of U and H, Hess’s law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization, sublimation, phase transition, ionization, solution and dilution. Second law of Thermodynamics (brief introduction)
    Introduction of entropy as a state function, Gibb’s energy change for spontaneous and nonspontaneous processes.
    Third law of thermodynamics (brief introduction).

    UNIT VI – Equilibrium

    Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant, factors affecting equilibrium – Le Chatelier’s principle, ionic equilibrium- ionization of acids and bases, strong and weak electrolytes, degree of ionization,
    ionization of poly basic acids, acid strength, concept of pH, hydrolysis of salts (elementary idea), buffer solution, Henderson Equation, solubility product, common ion effect (with illustrative examples).

    UNIT VII – Redox Reactions

    Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, in terms of loss and gain of electrons and change in oxidation number, applications of redox reactions.

    UNIT VIII – Organic Chemistry: Some basic Principles and Techniques

    General introduction, classification and IUPAC nomenclature of organic compounds. Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance and hyper conjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.

    UNIT IX – Hydrocarbons

    Classification of Hydrocarbons
    Aliphatic Hydrocarbons:
    Alkanes – Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions.
    Alkenes – Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markovnikov’s addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.
    Alkynes – Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of – hydrogen, halogens, hydrogen halides and water.

    Aromatic Hydrocarbons:

    Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Craft’s alkylation and acylation, directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.

    To know the CBSE Syllabus for all the classes from 1 to 12, visit the Syllabus page of CBSE. Meanwhile, to get the Practical Syllabus of Class 11 Chemistry, read on to find out more about the syllabus and related information in this page.

    CBSE Class 11 Chemistry Practical Syllabus with Marking Scheme

    In Chemistry subject, practical also plays a vital role in improving their academic scores in the subject. The overall weightage of Chemistry practical mentioned in the CBSE Class 11 Chemistry syllabus is 30 marks. So, students must try their best to score well in practicals along with theory. It will help in increasing their overall academic score.

    CBSE Class 11 Chemistry Practical Syllabus

    The experiments will be conducted under the supervision of subject teacher. CBSE Chemistry Practicals is for 30 marks. This contribute to the overall practical marks for the subject.

    The table below consists of evaluation scheme of practical exams.

    Evaluation SchemeMarks
    Volumetric Analysis08
    Salt Analysis08
    Content Based Experiment06
    Project Work04
    Class record and viva04
    Total30

    CBSE Syllabus for Class 11 Chemistry Practical

    Micro-chemical methods are available for several of the practical experiments. Wherever possible such techniques should be used.

    A. Basic Laboratory Techniques
    1. Cutting glass tube and glass rod
    2. Bending a glass tube
    3. Drawing out a glass jet
    4. Boring a cork

    B. Characterization and Purification of Chemical Substances
    1. Determination of melting point of an organic compound.
    2. Determination of boiling point of an organic compound.
    3. Crystallization of impure sample of any one of the following: Alum, Copper Sulphate, Benzoic Acid.

    C. Experiments based on pH

    1. Any one of the following experiments:

    • Determination of pH of some solutions obtained from fruit juices, solution of known and varied concentrations of acids, bases and salts using pH paper or universal indicator.
    • Comparing the pH of solutions of strong and weak acids of same concentration.
    • Study the pH change in the titration of a strong base using universal indicator.

    2. Study the pH change by common-ion in case of weak acids and weak bases.

    D. Chemical Equilibrium
    One of the following experiments:

    1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing the concentration of either of the ions.
    2. Study the shift in equilibrium between [Co(H2O)6] 2+ and chloride ions by changing the concentration of either of the ions.

    E. Quantitative Estimation
    i. Using a mechanical balance/electronic balance.
    ii. Preparation of standard solution of Oxalic acid.
    iii. Determination of strength of a given solution of Sodium hydroxide by titrating it against standard solution of Oxalic acid.
    iv. Preparation of standard solution of Sodium carbonate.
    v. Determination of strength of a given solution of hydrochloric acid by titrating it against standard Sodium Carbonatesolution.

    F. Qualitative Analysis
    1) Determination of one anion and one cation in a given salt
    Cations‐ Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Ni2+, Zn2+, Co2+, Ca2+, Sr2+, Ba2+, Mg2+, NH4 +
    Anions – (CO3)2‐ , S2‐, NO2 , SO32‐, SO2‐ , NO , Cl , Br, I‐, PO43‐ , C2O2‐ ,CH3COO
    (Note: Insoluble salts excluded)

    2) Detection of ‐ Nitrogen, Sulphur, Chlorine in organic compounds.

    G) PROJECTS
    Scientific investigations involving laboratory testing and collecting information from other sources.

    A few suggested projects are as follows:

    • Checking the bacterial contamination in drinking water by testing sulphide ion
    • Study of the methods of purification of water.
    • Testing the hardness, presence of Iron, Fluoride, Chloride, etc., depending upon the regional
      variation in drinking water and study of causes of presence of these ions above permissible
      limit (if any).
    • Investigation of the foaming capacity of different washing soaps and the effect of addition of
      Sodium carbonate on it.
    • Study the acidity of different samples of tea leaves.
    • Determination of the rate of evaporation of different liquids Study the effect of acids and
      bases on the tensile strength of fibres.
    • Study of acidity of fruit and vegetable juices.

    Note: Any other investigatory project, which involves about 10 periods of work, can be chosen with the approval of the teacher.

    Practical Examination for Visually Impaired Students of Class 11

    Below is a list of practicals for the visually impaired students.

    A. List of apparatus for identification for assessment in practicals (All experiments)
    Beaker, tripod stand, wire gauze, glass rod, funnel, filter paper, Bunsen burner, test tube, test tube stand,
    dropper, test tube holder, ignition tube, china dish, tongs, standard flask, pipette, burette, conical flask, clamp
    stand, dropper, wash bottle
    • Odour detection in qualitative analysis
    • Procedure/Setup of the apparatus

    B. List of Experiments A. Characterization and Purification of Chemical Substances
    1. Crystallization of an impure sample of any one of the following: copper sulphate, benzoic acid
    B. Experiments based on pH
    1. Determination of pH of some solutions obtained from fruit juices, solutions of known and varied
    concentrations of acids, bases and salts using pH paper
    2. Comparing the pH of solutions of strong and weak acids of same concentration.

    C. Chemical Equilibrium
    1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing
    the concentration of eitherions.
    2. Study the shift in equilibrium between [Co(H2O)6]2+ and chloride ions by changing the
    concentration of either of the ions.

    D. Quantitative estimation
    1. Preparation of standard solution of oxalic acid.
    2. Determination of molarity of a given solution of sodium hydroxide by titrating it against standard
    solution of oxalic acid.

    E. Qualitative Analysis
    1. Determination of one anion and one cation in a given salt
    2. Cations – NH+4
    Anions – (CO3)2-, S2-, (SO3)2-, Cl-, CH3COO-
    (Note: insoluble salts excluded)
    3. Detection of Nitrogen in the given organic compound.
    4. Detection of Halogen in the given organic compound.

    Note: The above practicals may be carried out in an experiential manner rather than recording observations.

    We hope students must have found this information on CBSE Syllabus useful for their studying Chemistry. Learn Maths & Science in interactive and fun loving ways with ANAND CLASSES (A School Of Competitions) App/Tablet.

    Frequently Asked Questions on CBSE Class 11 Chemistry Syllabus

    Q1

    How many units are in the CBSE Class 11 Chemistry Syllabus?

    There are 9 units in the CBSE Class 11 Chemistry Syllabus. Students can access various study materials for the chapters mentioned in this article for free at ANAND CLASSES (A School Of Competitions).

    Q2

    What is the total marks for practicals examination as per the CBSE Class 11 Chemistry Syllabus?

    The total marks for the practicals as per the CBSE Class 11 Chemistry Syllabus is 30. It includes volumetric analysis, content-based experiment, salt analysis, class record, project work and viva.

    Q3

    Which chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry?

    The organic chemistry chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry.