The p-block elements are known to be those elements in which the electron enters in one of the three orbitals of the p-block. There are 6 groups of p-block elements. The properties of p-block elements are that they are shiny and are good conductor of heat and electricity since they have free electrons. Let’s learn about interhalogen compounds,

Interhalogen Compounds, Properties, Preparation, Uses, FAQs

by

The p-block elements are known to be those elements in which the electron enters in one of the three orbitals of the p-block. There are 6 groups of p-block elements. The properties of p-block elements are that they are shiny and are good conductor of heat and electricity since they have free electrons. Let’s learn about interhalogen compounds,

Interhalogen Compounds

When halogen group elements react with each other, interhalogen compounds are created. In other terms, it’s a molecule made up of two or more distinct group 17 elements. The vast majority of known interhalogen compounds are binary in nature (composed of only two distinct elements). In general, their equations are XYn, where n = 1, 3, 5, or 7, and X is the less electronegative of the two halogens. Because halogens have odd valences, the value of n in interhalogens is always odd. They’re all susceptible to hydrolysis and ionization, resulting in poly halogen ions. Because astatine is extremely radioactive, those created with it have a very short half-life. Interhalogen chemicals are divided into four categories:

  1. Diatomic interhalogens (AX)
  2. Tetratomic interhalogens (AX3)
  3. Hexatomic interhalogens ( AX5)
  4. Octatomic interhalogens (AX7)

Properties of Interhalogen compounds

  1. These molecules are diamagnetic and covalent in nature.
  2. These chemicals form bonds that are more reactive than diatomic halogen bonds.
  3. These molecules’ physical properties are transitional between their constituents.
  4. AX3 molecules have a bent T shape.
  5. AX5 molecules are square or pyramidal.
  6. AX7 molecules have a bipyramidal or pentagonal structure.
  7. The length of the bond is determined by the size of the constituent halogens.
  8. Because of the increase in molecular weight, a molecule made up of lighter group 17 elements is rather colorless, whereas one made up of higher halogens is darker in color.
  9. The greater the difference in electronegativities between the two halogens in an interhalogen, the higher the boiling point of the interhalogen.

Diatomic interhalogens

The physical properties of the interhalogens of form XY are intermediate between those of the two-parent halogens. Because the less electronegative halogen, X, has been oxidized and has a partial positive charge, the covalent link between the two atoms has an ionic nature. All fluorine, chlorine, bromine, and iodine combinations with the above-mentioned general formula are known, but not all of them are stable. Some astatine-halogen combinations aren’t even known, and the ones that  are extremely unstable. The lightest interhalogen chemical, for example, is chlorine monofluoride which is an odorless and colorless gas.

Tetratomic interhalogens

Chlorine trifluoride (ClF3) is a colorless gas that condenses into a green liquid and solidifies into a white solid. It’s created in a nickel tube by reacting chlorine with an excess of fluorine at 250°C. It reacts more violently and explosively than fluorine. The molecule is T-shaped and flat. It is used while producing uranium hexafluoride.

Bromine trifluoride (BrF3) is the yellow-green liquid conducting electricity and self-ionizes into [BrF2]+ and [BrF4]–. When it reacts with metals or metal oxides, it does produce comparable ionized entities; while reacting with others, it produces metal fluoride and also free bromine and oxygen. It is utilized as a fluorinating agent in organic chemistry. Its molecular structure is identical to that of chlorine trifluoride.

Under pressure, iodine trichloride (ICl3) forms lemon-yellow crystals that melt into a brown liquid. It can be synthesized from the elements of iodine pentoxide and hydrogen chloride at low temperatures. It forms tetrachloroiodides (ICl4) when it reacts with several metal chlorides and then hydrolyzes in water. Each iodine atom is surrounded by four chlorine atoms in this planar dimer (ICl3)2.

Hexatomic interhalogens

A heavier halogen is coupled with five or seven fluorine atoms in all stable hexatomic and octatomic interhalogens. Fluorine atoms, unlike other halogens, have a strong electronegativity and a tiny size that allows them to be stabilized.

Chlorine pentafluoride (ClF5) is a colorless gas that is created by combining chlorine trifluoride and fluorine at high temperatures and pressures. Water, as well as most metals and nonmetals, reacts aggressively with it. Bromine pentafluoride (BrF5) is a colorless fuming liquid formed by mixing bromine trifluoride with fluorine at 200°C. Although it is physically stable, it reacts severely with water, metals, and nonmetals. Iodine pentafluoride (IF5) is a colorless liquid formed by the reaction of iodine pentoxide with fluorine or iodine with silver(II) fluoride. It has a strong reactivity, even when used with glass. It forms hydrofluoric acid when it combines with water, and iodine heptafluoride when it reacts with fluorine gas. The molecule has a tetragonal pyramid shape.

Octatomic interhalogens

The fluorinating agent iodine heptafluoride (IF7) is a colorless gas. Iodine pentafluoride is created by reacting it with fluorine gas. A pentagonal bipyramid is the shape of the molecule. This is the only interhalogen chemical known in which the bigger atom carries seven smaller atoms. All attempts to synthesis bromine or chlorine heptafluoride have failed; instead, bromine or chlorine pentafluoride, as well as fluorine gas, are created.

Preparation of Interhalogen compounds

Under some conditions, these molecules are generated by the direct combination of the action of a group 17 element with a lower interhalogen compound. For instance, at 437K, chlorine combines with an equal volume of fluorine to generate ClF. In the synthesis of group 17 fluorides, this approach is commonly employed.

Cl2 +F2  → 2ClF (473K)

I2 + Cl2  →2ICl

Uses of Interhalogen compounds

  1. These are solvents that are not aqueous in nature.
  2. In a few reactions, they act as a catalyst.
  3. These are fluorinating chemicals.

Sample Problems(FAQs)

Question 1: Why are interhalogen compounds covalent?

Solution:

Because of the low electronegativity difference between halogens, interhalogen compounds are covalent.

Question 2: What is the difference in the electronegativities of interhalogen compounds? 

Solution:

The polarisation of the link is caused by the variation in electronegativities of interhalogen chemicals. Interhalogen compounds are thus more reactive than halogens due to their polarity and poor bonding.

Question 3: Why Are Interhalogen Compounds More Reactive than Halogens? 

Solution:

Except for fluorine, interhalogen compounds are more reactive than all other halogens. Interhalogen compounds are more reactive than all other halogens because they all hydrolyze and ionise to form polyatomic ions. Because overlapping between orbitals of different atoms is less effective, interhalogen compounds have lower bond energies than halogens.

Question 4: What are Interhalogen Compounds? 

Solution:

Halogen subordinates are interhalogen compounds. Interhalogen compounds are those that include two separate types of halogens.

Question 5: Can Fluorine Ever Be a Central Atom?

Solution:

In interhalogen compounds, fluorine cannot be a core particle. This is due to the fact that it is part of the periodic table’s second cycle. It can only make one bond because it contains seven valence electrons.

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.

© 2025 Anand Classes • Published by Anand Technical Publishers
Privacy Policy Terms Contact

Sitemap