Sulphur is the tenth most prevalent element in the universe. It can also be found in the form of sulphide in a variety of meteorites. The existence of a sulphur element in molten, gaseous, and solid states gives the Jupiter moon lo its unusual colours. Sulphur is the sixth most prevalent element on Earth in terms of mass. Elemental sulphur is most commonly found near volcanic areas and hot springs. In the past, Sicily was the principal source of sulphur. Submarine volcanoes also result in the production of molten sulphur lakes, which are mostly found on the seafloor.

Allotropes of Sulphur-Rhombic sulphur (α-sulphur), Monoclinic sulphur (β-sulphur), Colloidal Sulphur, Physical & Chemical Properties of Sulphur

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Sulphur is the tenth most prevalent element in the universe. It can also be found in the form of sulphide in a variety of meteorites. The existence of a sulphur element in molten, gaseous, and solid states gives the Jupiter moon lo its unusual colours. Sulphur is the sixth most prevalent element on Earth in terms of mass. Elemental sulphur is most commonly found near volcanic areas and hot springs. In the past, Sicily was the principal source of sulphur. Submarine volcanoes also result in the production of molten sulphur lakes, which are mostly found on the seafloor.

Anaerobic bacteria’s action on sulphate minerals such as gypsum results in the synthesis of native sulphur. Previously, commercial production was based on fossil-based sulphur deposits from gypsum in salt domes. This process, however, is not currently the primary source of sulphur for commercial use. Many valuable metal ores, such as galena, blende, and gypsum, are sulphur compounds. It can be found in the ores as sulphides or sulphates. Sulfur compounds can also be found in natural gas, petroleum, and coal.

Sulphur

The element sulphur, often known as sulfur, is one of the most reactive elements in the periodic table. It is a non-metal that belongs to the periodic table’s group 16 (VI A). 

This chemical element has an atomic number of 16 and is symbolized as S. 

The elemental sulphur is a crystalline solid with a vivid yellow colour at room temperature. The element sulphur is prevalent throughout the universe. Sulfur has been used by humans since the dawn of time. Brimstone, which means “firestone,” was the name given to it in the past.

Physical Properties of Sulphur

  1. When found naturally, sulphur has a yellowish colour and is frequently found as a crystal.
  2. At room temperature, sulphur is non-reactive. Sulfur or sulphur can combine to form a variety of polyatomic molecules.
  3. S8, also known as octa-sulfur, is one of the most common sulphur molecules. It is a soft, odourless solid with a bright yellow colour. This molecule has a melting point of 115.21 degrees Celsius and a boiling point of 444.6 degrees Celsius. When this molecule is between its melting and boiling points, it polymerizes, resulting in increased viscosity but lower density.
  4. Depolymerization occurs at higher temperatures, resulting in decreased viscosity.
  5. Depending on the allotrope, the density varies.
  6. All stable sulphur allotropes do not allow electricity to pass through them. As a result, they are excellent electrical insulators.

Chemical Properties of Sulphur

  1. Sulfur combustion produces a blue flame and an unpleasant odour due to the formation of sulphur dioxide.
  2. Sulfur is insoluble in water but slightly soluble in nonpolar organic solvents such as benzene.
  3. This element’s most common oxidation states are +4 and +6.
  4. Sulfur is highly reactive and almost all elements react with it, including iridium, which is highly unreactive except for noble gases.
  5. Sulfur compounds have many unusual properties, including the ability to catenate in the same way that carbon does.
  6. Sulphur’s properties allow it to form chain structures as well as a ring system, similar to carbon.
  7. One of the most well-known sulphur compounds is hydrogen sulphide (H2S). It is a colourless, poisonous gas that smells like rotten eggs. It is naturally present in mineral water and volcanoes as vapours. A large amount of hydrogen sulphide is produced during the sulphur removal process from petroleum.
  8. Sulfur and oxygen can also combine to form a variety of compounds. Sulfur dioxide, a poisonous and colourless gas, is the most well-known sulphur oxide.
  9. In addition, it is used as a reducing agent and bleach in a variety of industries. It was also used by scientists to produce sulphur trioxide. This oxide is also beneficial in the ripening of fruits and the preservation of food.

Uses of Sulphur

  • Sulfur is required for the synthesis of other essential chemicals. Sulfuric acid, the most important chemical produced by sulphur, has numerous industrial applications.
  • The reaction of sulphur with methane produces carbon disulfide, which is required for the production of rayon and cellophane.
  • Another important application of sulphur is in the vulcanization of rubber.
  • Organosulfur compounds are found in a wide range of pharmaceutical products. It is also found in a variety of agrochemicals and dyestuffs.
  • Since ancient times, people have used elemental sulphur as pesticides and fungicides. Dusting sulphur (powdered sulphur) is a common pesticide used in organic farming.
  • Sulfur plays an important role in the body and is required for the synthesis of certain proteins. Sulfur, for example, is required for the synthesis of glutathione, which acts as a powerful antioxidant to protect your cells from damage.
  • While sulphur found in foods is beneficial to the body, there is little evidence that taking sulphur supplements is beneficial.
  • Sulfur is an FDA-approved ingredient for use in over-the-counter dandruff products. It is frequently used in conjunction with salicylic acid. However, there is limited evidence to support that use.
  • Sulfur supplements are frequently used to treat osteoarthritis.
  • When used topically, sulphur may be safe. Sulfur-containing products containing up to 10% sulphur have been used safely in clinical studies lasting up to eight weeks.

Allotropes of Sulphur

Sulphur generates a number of allotropes. The first is yellow rhombic sulphur (α-sulphur), and the second is monoclinic sulphur (β-sulphur). The most intriguing feature is that the allotropes of the sulphur compound are interconvertible in terms of thermal stability. It means that rhombic sulphur produces monoclinic sulphur when heated above 369K.

Rhombic sulphur (α-sulphur)

Rhombic sulphur is a crystalline substance with an octahedral shape. When we heat the roll sulphur solution in the CS2, we get rhombic sulphur. It has a yellow colour, a specific gravity of 2.06, and a melting point of 385.8K. Rhombic sulphur compounds are not soluble in water, but they are soluble in ether, benzene, or alcohol.

Monoclinic sulphur (β-sulphur)

When we melt rhombic sulphur in a dish and cool it, we get monoclinic sulphur. In this process, we poke two holes in the crust and pour out the remaining liquid. When the crust is removed after this process, we get colourless needle-shaped crystals of -sulphur.

Colloidal Sulphur

It is created by passing hydrogen sulphide through a saturated and cooled sulphur dioxide solution in water. The other method is to mix an alcohol and sulphur solution into the water. It also serves as a solvent in the carbon disulfide reaction. It can be used in pharmaceuticals.

Sample Questions (FAQs)

Question 1: What are the three common uses of sulfur?

Answer:

It is used in the production of automobile batteries, fertiliser, oil refining, water treatment, and mineral extraction. Other uses for sulfur-based chemicals include rubber vulcanization, bleaching paper, and the manufacture of products such as cement, detergents, and pesticides.

Question 2: How does one get sulfur naturally?

Answer:

Sulfur is extracted from natural gas, coal, crude oil, and other sources such as flue dust and gases produced during the processing of metal sulphide ores. Elemental sulphur can be obtained in a variety of forms, such as sulphur flowers, fine crystalline powder, and roll sulphur.

Question 3: What is the Biological Role of the Sulphur?

Answer:

Sulphur is an important component of every living cell. It is found in equal amounts in the human body as potassium. The majority of sulphur in plants and animals is found in the form of amino acids. Eggs are heavy in sulphur, which helps chicks’ feathers grow. The smell of decaying eggs is caused by hydrogen sulphide production. Sulfur’s role in the cell is to decrease hydrogen and its electrons, allowing for cellular repair.

Question 4: What are some chemical properties of sulphur?

Answer:

Due to the creation of sulphur dioxide, burning sulphur generates a blue flame and a disagreeable odour. Sulfur is water insoluble but somewhat soluble in non-polar organic solvents such as benzene. This element’s most prevalent oxidation states are +4 and +6. Except for noble gases, sulphur is highly reactive and almost reacts with all elements, including iridium, which is rather unreactive.

Question 5: What is octa-sulphur?

Answer:

S8, also known as octa-sulfur, is a sulphur molecule. It’s a spongy, odourless solid with a bright yellow colour. This molecule polymerizes when it is between its melting and boiling temperatures, resulting in increased viscosity but lower density.

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.

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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.

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