Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Oxoacids of Phosphorus-Phosphorus acid, Phosphoric acid, Hypophosphoric Acid, Pyrophosphoric Acid, Orthophosphoric Acid, Structures, Properties, Uses, FAQS

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Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

P-H bonds in oxoacids cannot be ionizable to produce H+ ions. The H atoms bonded to oxygen in P-OH form, on the other hand, are ionizable. As a result, we can state that basicity is a feature exhibited by H atoms coupled to oxygen. As a result of the two P-OH linkages, phosphorous acid, H3PO3, is dibasic. Similarly, phosphoric acid, H3PO4, is tribasic due to the presence of three P-OH bonds. Phosphorus oxoacids with P-H bonds have significant reducing capabilities. Hypophosphorous acid, which has two P-H bonds, is an excellent reducing agent.

4AgNO3 + 2H2O + H3PO2 → 4Ag + 4HNO3 + H3PO4

Oxoacids of Phosphorus

Diprotic acid is phosphoric acid. It ionizes two protons as a result of this. The structural formula HPO(OH)2 is a better way to represent it. Phosphorous acid can be made by hydrolyzing phosphorus trichloride with acid or steam.

PCl3 + 3H2O → HPO(OH)2 + 3HCl

Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Phosphorus acid

Phosphoric acid is classified as a triprotic acid. This indicates it has the ability to ionize three protons. When pure, it is a non-toxic acid. At room temperature and pressure, it is solid. Phosphoric acid can be made by adding sulfuric acid to tricalcium phosphate rock:

Ca5(PO4)3X + 5H2SO4 + 10H2O → 3H3PO4 + 5CaSO4.2H2O + HX

(X can be F, Cl, Br, and OH)

Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Phosphoric acid

  • Meta phosphoric Acid (HPO3)n

We can get it by heating orthophosphoric acid at around 850 degrees Celsius. As a monomer, it does not exist. It comes in the form of a cyclic trimer, cyclic tetramer, or polymer.

H3PO4 → HPO3 + H2O

  • Hypophosphoric Acid (H4P2O6)

By performing controlled oxidation of red phosphorus with sodium chlorite, hypophosphoric acid is formed. Once the disodium salt of the acid is generated, it passes through a cation exchanger to produce hypophosphoric acid. The acid is tetrabasic in nature.

2P + 2NaClO2 + 2H2O → Na2H2P2O6 + 2HCl

Na2H2P2O6 + 2H → H4P2O6 + 2Na

Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Hypophosphoric Acid

  • Pyrophosphoric Acid (H4P2O7)

When orthophosphoric acid is heated to near 250°C, it transforms into tetrabasic acid.

2H3PO4 → H4P2O7 + H2O

Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Pyrophosphoric Acid

  • Orthophosphoric Acid (H3PO4)

When P4O10 is treated with bubbled water, orthophosphoric acid is produced. This acid has a tribasic structure.

P4O10+6H2O → 4H3PO4

Oxoacids are acids that contain oxygen. Phosphorus is one such element that can be used to create a variety of oxoacids. H3PO4, H3PO3, and other common oxyacids The phosphorus atom is tetrahedrally surrounded by other atoms in phosphorus oxoacids. In general, it is obvious that these acids have at least one P=O bond and one P–OH bond. In addition to P=O and P–OH links, phosphorus oxoacids have P–P or P–H bonds. In these circumstances, the phosphorus oxidation state is less than +5. These acids are known to bounce between higher and lower oxidation states. For example, when heated, phosphorous acid decomposes into phosphoric acid and phosphine. 

Orthophosphoric Acid

Acidic Strength

Acidic strength order of the Oxoacids of Phosphorus: H₃PO₂, H₃PO₃, and H₃PO₄

The order of phosphorus acidity strength of oxoacids: H3PO4 > H3PO3 > H3PO2.

In the first example, all hydrogen atoms are connected to an oxygen atom as an OH group, which allows hydrogen to be easily released as protons. As a result, the acidity of phosphorus oxyacids will be the highest. In the second situation, two hydrogen atoms are bonded to the oxygen atoms, while a third hydrogen atom is attached to the P atom, which cannot be released as a proton.

Finally, only one hydrogen atom is bonded to oxygen in the third scenario, while the other two hydrogen atoms are attached directly to P, which cannot come out as protons. Furthermore, only one hydrogen can be produced as a proton. As a result, the acidity of a protonic acid is determined by how easily the species releases the H+ ion. As a result, the above-mentioned order is the result.

Basic Strength phosphorus oxoacids

The basicity of phosphorus oxoacids is defined as the number of ionizable H+ ions or protons in that acid. Although the structure of Phosphorus Oxoacids contains three H atoms, only those directly linked to the Oxygen (O) atom are easily ionized. However, there are only two such H atoms. As a result, the basicity of phosphorus oxoacids is 3.

Uses of Oxoacids of Phosphorus

Among the many applications for phosphorus oxoacids are:

  1. Phosphorus is utilized as a sulfuric acid replacement in the production of HI and HBr.
  2. It is used in the manufacture of soft drinks as a souring agent.
  3. It is utilized in the production of sodium, ammonium, and potassium phosphate salts.
  4. It’s utilized in the production of phosphatic fertilizers.

Sample Problems (FAQS)

Question 1: How do we obtain Hypophosphoric Acid?

Answer:

The controlled oxidation of red phosphorus with sodium chlorite can produce this acid. When we obtain the hypophosphoric acid disodium salt, we run it via a cation exchanger to obtain hypophosphoric acid. It has a tetrabasic structure.

Question 2: Is H3PO2 an acid?

Answer:

If we look at the structure of Phosphorus Oxoacids, we can see that P is attached to an oxygen atom with a double bond, two hydrogens with every single bond, and finally to a hydroxyl group. Acids are organic substances that can produce free H+ ions. There are three hydrogens in the chemical described above. The basicity here is 2, but the hydrogen connected to the electronegative atom, to the oxygen atom, is transferred as a hydrogen ion. This could lead to confusion. Because P-H bonds are stronger than O-H bonds in this case, the weaker link is easily broken. This chemical is definitely an acid because it can produce an H+ ion.

Question 3: What are Oxoacids?

Answer:

To put it simply, oxyacids are acids that contain oxygen. One of these elements is phosphorus, which can be found in a variety of oxoacids. Examples include H3PO4, H3PO3, and various oxyacids.

Question 4: Why is H3PO3 dibasic?

Answer: 

The phosphorus atom is connected by two -OH groups, and one hydrogen atom is bonded directly to the phosphorus atom. It is simple to break the O-H bond. As a result, the two -OH groups are responsible for this compound’s diprotic nature. Whereas another Hydrogen is directly connected to the phosphorus atom, the bond is difficult to break due to its high stability. As a result, it is a diprotic acid rather than a triprotic acid.

Question 5: Write a short note on the basic strength of phosphorus oxoacids?

Answer:

The number of ionizable H+ ions or protons in phosphorus oxoacids is defined as the acid’s basicity. Although Phosphorus Oxoacids have three H atoms in their structure, only those immediately connected to the Oxygen (O) atom are easily ionised. There are, however, only two such H atoms. As a result, phosphorus oxoacids have a basicity of 3.

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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