Phosphorus is required for life, mostly through phosphates, which are molecules that contain the phosphate ion. Phosphates are found in DNA, RNA, ATP, and phospholipids, which are all complex molecules that are required by cells. Phosphate was first found in human urine, and bone ash was a significant early source of phosphate. Phosphate mines contain fossils because phosphate is found in fossilized deposits of animal remnants and excreta. In some aquatic environments, low phosphate levels constitute a substantial growth limitation. The majority of the phosphorus compounds collected are utilized to create fertilizers.

Phosphorus Halides-Structure, Properties, Uses, Effects of Phosphorus Trichloride(PCl3) & Phosphorus Pentachloride (PCl5)

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Phosphorus is required for life, mostly through phosphates, which are molecules that contain the phosphate ion. Phosphates are found in DNA, RNA, ATP, and phospholipids, which are all complex molecules that are required by cells. Phosphate was first found in human urine, and bone ash was a significant early source of phosphate. Phosphate mines contain fossils because phosphate is found in fossilized deposits of animal remnants and excreta. In some aquatic environments, low phosphate levels constitute a substantial growth limitation. The majority of the phosphorus compounds collected are utilized to create fertilizers.

Properties of Phosphorus

  1. Phosphorus is a multivalent nonmetal with a nitrogen group. It can be found in nature in a variety of allotropic forms and is essential for organisms to survive.
  2. Phosphorus is classified into three types: white, red, and black phosphorous, however, their colors may range significantly.
  3. The industrial variation is white phosphorous, which lights in the dark, is spontaneously combustible when exposed to air, and is a fatal toxin.
  4. Red phosphorous can range in color from orange to purple due to tiny changes in its chemical structure.
  5. The third form, black phosphorous, is created under high pressure, resembles graphite, and may conduct electricity like graphite.

Oxidation State of Phosphorus

  1. Phosphorus, like nitrogen, has oxidation states of +3 or 3, depending on the electronegativity of the elements it mixes with.
  2. The main difference between nitrogen and phosphorus is that the latter has substantially lower electronegativity and bigger atoms with available outer d orbitals.
  3. Because of this, the similarities between nitrogen and phosphorus chemistry are primarily formal, concealing the underlying, considerable differences.
  4. The outer d orbitals of phosphorus allow for octet expansion, resulting in the +5 state, in which five genuine covalent bonds are formed in compounds, a condition that nitrogen cannot achieve.

Uses of Phosphorus

  1. Phosphorus is now extensively utilized in four forms: white, black, red, and violet.
  2. Phosphorus may be found easily on the periodic table at position fifteen, just below nitrogen (N).
  3. Phosphorus can be found in a variety of products, including fireworks, fertilizers, and baking powder.
  4. Phosphorus is also utilized in steel manufacturing.
  5. Phosphates are also utilized to make fine china and special glassware.

Phosphorus Halides

A phosphorus halide is a chemical formed when phosphorus reacts with halogen. There are two kinds of phosphorus halides. PX3 and PX5 are the model numbers. In this case, X represents a halogen. Fluorine, chlorine, bromine, or iodine are all possibilities. The most prevalent phosphorus halide, however, is chloride. These chlorides are often covalent in character.

Phosphorus Trichloride(PCl3)

This fluid is slick and smooth. It is extremely lethal in nature. This compound has the shape of a triangular pyramid. The phosphorus atom displays sp3 hybridization. Phosphorus has sp3 orbitals, as shown in the diagram above. It only contains one electron, which it transfers to a p orbital electron from three chlorine atoms. The fourth sp3 orbital is completely filled. It’s just the two of them. As a result, it is unable to make a bond. It does, however, reject alternative bonds. This results in a state of trigonal pyramidal shape.

Preparation of Phosphorus trichloride (PCl3)

  • Phosphorus trichloride is produced by passing dry chlorine overheated white phosphorus. The following is the reaction that occurs:

P4 + 6Cl2 → 4PCl3

  • This chemical can alternatively be synthesized by reacting thionyl chloride with white phosphorus.

P + 8SOCl2 → 4PCl3 + 4SO2 + 2S2Cl2

Chemical Properties Phosphorus trichloride (PCl3)

  • When we dampen phosphorus trichloride, it hydrolyzes.

PCl3 + 3H2O → H3PO3 + 3HCl

  • It combines with natural compounds containing a –OH group, producing ‘chloro’ subsidiaries as a byproduct.

3C2H5OH + PCl3 → 3C2H5Cl + H3PO3

Uses of Phosphorus trichloride (PCl3)

  1. It is commonly employed as a key reagent in organic chemistry to replace the hydroxyl group with a chlorine atom.
  2. It is oxidized with oxygen to produce phosphorus oxychloride.
  3. It is utilized in the manufacture of phosphate ester insecticides.
  4. It is utilized to make chlorinated chemicals such as phosphorous pentachloride, phosphoryl chloride, thiophosphoryl chloride, and pseudohalogens.

Structure of Phosphorus trichloride (PCl3)

The phosphorus particle in the center of PCl3 is hybridized with sp3. It consists of three bond sets and one lone pair of electrons. As a result, it has a pyramidal shape. It functions as a Lewis base because it can transfer its lone pair of electrons to other electron-deficient particles or atoms.

Phosphorus Pentachloride

It has a yellowish-white color to it. Phosphorus pentachloride is a water-sensitive solid. Organic solvents such as carbon tetrachloride, benzene, carbon disulfide, and diethyl ether dissolve it. It has the shape of a trigonal bi-pyramid. This structure is mostly found in the vaporous and fluid stages. It exists as an ionic solid in the solid form, [PCl4]+[PCl6]–. The cation, [PCl4]+, is tetrahedral in this case, and the anion, [PCl6]– is octahedral. The molecule must have three tropical P-Cl bonds and two crucial P-Cl bonds. Because of the stronger repulsion at hub positions compared to central positions, the two axial bonds are longer than tropical bonds.

Preparation of Phosphorus Pentachloride (PCl5)

  • The reaction with an excess of dry chlorine can be used to make pentachloride.

P4 + 10Cl2 → 4PCl5

  • We can also make it by combining SO2Cl2 with phosphorous.

P4 + 10SO2Cl2 → 4PCl5 + 10SO2

Chemical Properties Phosphorus Pentachloride (PCl5)

  • Phosphorus pentachloride hydrolyzes to POCl3 in the presence of wet air. Over time, this molecule degrades into phosphoric acid.

PCl5 + H2O → POCl3 + 2HCl

  • When we heat it, it sublimes and disintegrates further into phosphorus trichloride.
  • Under the action of heat, it interacts with finely partitioned metals to form metal chlorides.

Uses of Phosphorus Pentachloride (PCl5)

  • It is used to chlorinate water.
  • It is used in the pharmaceutical industry to make penicillin and cephalosporin.
  • It is used in the production of acid chlorides.
  • It is used as a catalyst in the production of acetyl cellulose, as well as a catalyst in condensation processes and cyclization.

Structure of Phosphorus Pentachloride (PCl5)

In phosphorus pentachloride, the central phosphorus atom undergoes sp3d hybridization. As bond sets, all five electrons unite in these hybrid orbitals. The particle has a trigonal bipyramidal molecular form. We receive five electrons of equal size and form after the five electrons are hybridized. In the center, three of them form a triangle (120° partition). One bond is above those three, and one is beneath them. However, keep in mind that trigonal bipyramidal geometry in phosphorus pentachloride is only visible in its fluid and vaporous states. It exists as salt in its solid-state.

Harmful Effects of Phosphorus Pentachloride (PCl5)

Phosphorus Pentachloride is a chemical that is reactive. Direct Phosphorus Pentachloride exposure might result in fatigue, nausea, headache, dizziness, and vomiting. It has the potential to harm the liver and kidneys. Phosphorus Pentachloride must be identified as a precaution. It is a crystalline substance with a pungent odor and a color ranging from white to pale yellow. Phosphorus Pentachloride is a chemical that is used in the production of various chemicals, aluminum metallurgy, and the pharmaceutical sector. The following are some of the serious health risks that Phosphorus Pentachloride can cause:

  1. Individuals who come into contact with Phosphorus Pentachloride may have severe irritation and burning of the skin and eyes, as well as permanent eye impairment.
  2. Breathing in Phosphorus Pentachloride can cause nose and throat discomfort.
  3. It can cause severe irritation and damage to the lungs if inhaled deeply, resulting in coughing and/or shortness of breath. Increased exposure to Phosphorus Pentachloride can also result in a medical emergency. This can result in pulmonary edema, or fluid buildup in the lungs, as well as severe shortness of breath.
  4. Phosphorus Pentachloride exposure might result in coughing, phlegm, and bronchitis.

Sample Problems (FAQS)

Question 1: What are the main sources of phosphorus?

Answer:

Phosphorus is abundant in protein meals such as milk and milk derivatives, as well as meat substitutes such as beans, lentils, and nuts. Phosphorus can be found in cereals, especially whole grains. Phosphorus concentrations are lower in vegetables and fruits.

Question 2: What makes phosphorus unique?

Answer:

Phosphorus, with the exception of black phosphorus, is a poor conductor of heat and electricity. All types of phosphorus are stable at normal temperature. The white allotrope (also known as yellow phosphorus) is wax-like, the red and purple allotropes are non-crystalline solids, and the black allotrope is graphite in pencil lead.

Question 3: Which phosphorus is used in matchstick? 

Answer:

When you strike the match, a small amount of red phosphorus on the striking surface is converted to white phosphorous, which ignites. The heat from this ignites the potassium chlorate, resulting in the match head bursting into flame.

Question 4: Mention some of the common uses of phosphorus halides.

Answer: 

The following are some of the applications for Phosphorus Halides:

  1. As a chlorinating agent, we use phosphorus halides. It is specifically used to clean bodies of water.
  2. We also use them to make water treatment agents. We utilise them far too regularly to create organophosphorus insecticides.
  3. They are also a major component of lubricant and paint additives. In these substances, they serve as an intermediary.
  4. Phosphorus halides are used in the production of phosphorus acid. As an intermediary, we also employ them to make chloroanhydrides and phosphoric acid subsidiaries.

Question 5: What is the structure of phosphorus pentachloride?

Answer:

In phosphorus pentachloride, the central phosphorus atom undergoes sp3d hybridization. As bond sets, all five electrons unite in these hybrid orbitals. The particle has a trigonal bipyramidal molecular form. We receive five electrons of equal size and form after the five electrons are hybridised.

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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