p-Block Elements:NCERT Exemplar Solutions for Class 12 Chemistry, Important Questions

February 15, 2025December 26, 2024 by Neeraj Anand, Param Anand

p-Block Elements:NCERT Exemplar Solutions for Class 12 Chemistry

I. Multiple Choice Questions (Type-I)

1. On addition of conc. H2SO4 to a chloride salt, colourless fumes are evolved but in case of an iodide salt, violet fumes come out. This is because

(i) H2SO4 reduces HI to I2

(ii) HI is of violet colour

(iii) HI gets oxidised to I2

(iv) HI changes to HIO3

Solution:

Option (iii) is the answer.

2. In qualitative analysis when H2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives _________.

(i) a deep blue precipitate of Cu (OH)2

(ii) a deep blue solution of [Cu (NH3)4]2+

(iii) a deep blue solution of Cu(NO3)2

(iv) a deep blue solution of Cu(OH)2.Cu(NO3)2

Solution:

Option (ii) is the answer.

3. In a cyclotrimetaphosphoric acid molecule, how many single and double

bonds are present?

(i) 3 double bonds; 9 single bonds

(ii) 6 double bonds; 6 single bonds

(iii) 3 double bonds; 12 single bonds

(iv) Zero double bonds; 12 single bonds

Solution;

Option (iii) is the answer.

4. Which of the following elements can be involved in pπ–dπ bonding?

(i) Carbon

(ii) Nitrogen

(iii) Phosphorus

(iv) Boron

Solution:

Option (iii) is the answer.

5. Which of the following pairs of ions are isoelectronic and isostructural?

(i) CO3^2-, NO^3-

(ii) ClO^3- , CO3^2-

(iii) SO3^2-, NO^3-

(iv) ClO^3- , SO3²^–Solution:

Option (i) is the answer.

6. Affinity for hydrogen decreases in the group from fluorine to iodine. Which of

the halogen acids should have the highest bond dissociation enthalpy?

(i) HF

(ii) HCl

(iii) HBr

(iv) HI

Solution:

Option (i) is the answer.

7. Bond dissociation enthalpy of E—H (E = element) bonds are given below. Which

of the compounds will act as the strongest reducing agent?

Compound ∆diss (E—H)/kJ mol–1

NH3 389

PH3 322

AsH3 297

SbH3 255

(i) NH3

(ii) PH3

(iii) AsH3

(iv) SbH3

Solution:

Option (iv) is the answer.

8. On heating with concentrated NaOH solution in an inert atmosphere of CO2, white phosphorus gives a gas. Which of the following statement is incorrect about the gas?

(i) It is highly poisonous and has smelled like rotten fish.

(ii) It’s a solution in water decomposes in the presence of light.

(iii) It is more basic than NH3

(iv) It is less basic than NH3

Solution:

Option (iii) is the answer.

9. Which of the following acids forms three series of salts?

(i) H3PO2

(ii) H3BO3

(iii) H3PO4

(iv) H3PO3

Solution:

Option (iii) is the answer.

10. Strong reducing behaviour of H3PO2 is due to

(i) The low oxidation state of phosphorus

(ii) Presence of two –OH groups and one P–H bond

(iii) Presence of one –OH group and two P–H bonds

(iv) High electron gain enthalpy of phosphorusSolution:

Option (iii) is the answer.

11. On heating lead, nitrate forms oxides of nitrogen and lead. The oxides formed

are ______.

(i) N2O, PbO

(ii) NO2, PbO

(iii) NO, PbO

(iv) NO, PbO2

Solution;

Option (ii) is the answer.

12. Which of the following elements does not show allotropy?

(i) Nitrogen

(ii) Bismuth

(iii) Antimony

(iv) Arsenic

Solution:

Option (i) is the answer.

13. Maximum covalency of nitrogen is ______________.

(i) 3

(ii) 5

(iii) 4

(iv) 6

Solution:

Option (iii) is the answer.

14. Which of the following statements is wrong?

(i) Single N–N bond is stronger than the single P–P bond.

(ii) PH3 can act as a ligand in the formation of a coordination compound

with transition elements.

(iii) NO2 is paramagnetic.

(iv) Covalency of nitrogen in N2O5 is four

Solution:

Option (i) is the answer.

15. A brown ring is formed in the ring test for NO3

–

ion. It is due to the formation of

(i) [Fe(H2O)5 (NO)]2+

(ii) FeSO4.NO2

(iii) [Fe(H2O)4 (NO)]2+

(iv) FeSO4.HNO3

Solution:

Option (i) is the answer.

16. Elements of group-15 form compounds in +5 oxidation state. However,

bismuth forms only one well-characterised compound in +5 oxidation state.

The compound is

(i) Bi2O5

(ii) BiF5

(iii) BiCl5

(iv) Bi2S5

Solution:

Option (ii) is the answer.

17. On heating ammonium dichromate and barium azide separately we get

(i) N2 in both cases

(ii) N2 with ammonium dichromate and NO with barium azide

(iii) N2O with ammonium dichromate and N2 with barium azide

(iv) N2O with ammonium dichromate and NO2 with barium azide

Solution:

Option (i) is the answer.

18. In the preparation of HNO3, we get NO gas by catalytic oxidation of ammonia.

The moles of NO produced by the oxidation of two moles of NH3

will be ______.

(i) 2

(ii) 3

(iii) 4

(iv) 6

Solution:

Option (i) is the answer.

19. The oxidation state of a central atom in the anion of compound NaH2PO2 will

be ______.

(i) +3

(ii) +5

(iii) +1

(iv) –3

Solution:

Option (iii) is the answer.

20. Which of the following is not tetrahedral in shape?

(i) NH4+

(ii) SiCl4

(iii) SF4

(iv) SO42–Solution:

Option (iii) is the answer.

21. Which of the following are peroxoacids of sulphur?

(i) H2SO5 and H2S2O8

(ii) H2SO5 and H2S2O7

(iii) H2S2O7 and H2S2O8

(iv) H2S2O6 and H2S2O7

Solution:

Option (i) is the answer.

22. Hot conc. H2SO4 acts as a moderately strong oxidising agent. It oxidises both metals and nonmetals. Which of the following element is oxidised by conc H2SO4 into two gaseous products?

(i) Cu

(ii) S

(iii) C

(iv) Zn

Solution:

Option (iii) is the answer.

23. A black compound of manganese reacts with a halogen acid to give greenish yellow gas. When an excess of this gas reacts with NH3 an unstable trihalide is formed. In this process the oxidation state of nitrogen changes from _________.

(i) – 3 to +3

(ii) – 3 to 0

(iii) – 3 to +5

(iv) 0 to – 3

Solution:

Option (i) is the answer.

24. In the preparation of compounds of Xe, Bartlett had taken O2+Pt F6– as a base compound. This is because

(i) both O2 and Xe has the same size.

(ii) both O2 and Xe has the same electron gain enthalpy.

(iii) both O2 and Xe has almost same ionisation enthalpy.

(iv) both Xe and O2 are gases.Solution:

Option (iii) is the answer.

25. In solid state PCl5 is a _________.

(i) covalent solid

(ii) octahedral structure

(iii) ionic solid with [PCl6]+ octahedral and [PCl4]– tetrahedra

(iv) ionic solid with [PCl4]+tetrahedral and [PCl6]– octahedral

Solution:

Option (iv) is the answer.

26. Reduction potentials of some ions are given below. Arrange them in decreasing

order of oxidising power.

Ion Reduction potential Eᶱ/V

ClO4^– Eᶱ = 1.19V

IO4^– Eᶱ = 1.65V

BrO4 – Eᶱ = 1.74V

(i) ClO4–> IO4–> BrO4–

(ii) IO4–> BrO4–> ClO4–

(iii) BrO4–> IO4–> ClO4–

(iv) BrO4–> ClO4–> IO4^–

Solution:

Option (iii) is the answer.

27. Which of the following is isoelectronic pair?

(i) ICl2, ClO2

(ii) BrO2–, BrF2+

(iii) ClO2, BrF

(iv) CN–, O3

Solution:

Option (ii) is the answer.

II. Multiple Choice Questions (Type-II)

Note: In the following questions two or more options may be correct.

28. If chlorine gas is passed through a hot NaOH solution, two changes are observed

in the oxidation number of chlorine during the reaction. These are ________

and _________.

(i) 0 to +5

(ii) 0 to +3

(iii) 0 to –1

(iv) 0 to +1

Solution:

Option (i) and (iii) are the answers.

29. Which of the following options are not in accordance with the property

mentioned against them?

(i) F2> Cl2> Br2> I2 Oxidising power.

(ii) MI > MBr > MCl > MF Ionic character of metal halide.

(iii) F2> Cl2> Br2> I2 Bond dissociation enthalpy.

(iv) HI < HBr < HCl < HF Hydrogen-halogen bond strength.

Solution:

Option (ii) and (iii) are the answers

30. Which of the following is correct for P4 the molecule of white phosphorus?

(i) It has 6 lone pairs of electrons.

(ii) It has six P–P single bonds.

(iii) It has three P–P single bonds.

(iv) It has four lone pairs of electrons.

Solution:

Option (ii) and (iv) are the answers.

31. Which of the following statements are correct?

(i) Among halogens, radius ratio between iodine and fluorine is maximum.

(ii) Leaving F—F bond, all halogens have weaker X—X bond than X—X’

bond in interhalogens.

(iii) Among interhalogen compounds, the maximum number of atoms are present

in iodine fluoride.

(iv) Interhalogen compounds are more reactive than halogen compounds.

Solution:

Option (i), (iii) and (iv) are the answers.

32. Which of the following statements are correct for SO2 gas?

(i) It acts as a bleaching agent in moist conditions.

(ii) Its molecule has linear geometry.

(iii) It’s dilute solution is used as a disinfectant.

(iv) It can be prepared by the reaction of dilute H2SO4

with metal sulphide.

Solution:

Option (i) and (iii) are the answers.

33. Which of the following statements are correct?

(i) All three N—O bond lengths in HNO3 are equal.

(ii) All P—Cl bond lengths in PCl5 molecule in the gaseous state are equal.

(iii) P4 molecule in white phosphorus have angular strain therefore white

phosphorus is very reactive.

(iv) PCl is ionic in the solid-state in which cation is tetrahedral and the anion is

octahedral.

Solution:

Option (iii) and (iv) are the answers.

34. Which of the following orders are correct as per the properties mentioned against

each?

(i) As2O3< SiO2< P2O3< SO2 Acid strength.

(ii) AsH3< PH3< NH3 Enthalpy of vaporization.

(iii) S < O < Cl < F More negative electron gain enthalpy.

(iv) H2O > H2S > H2Se > H2Te Thermal stability.

Solution:

Option (i) and (iv) are the answers.

35. Which of the following statements are correct?

(i) S–S bond is present in H2S2O6

(ii) In peroxosulphuric acid (H2SO5) sulphur is in +6 oxidation state.

(iii) Iron powder along with Al2O3 and K2O is used as a catalyst in the preparation of NH3

by Haber’s process.

(iv) Change in enthalpy is positive for the preparation of SO3

by catalytic oxidation of SO2

Solution:

Option (i) and (ii) are the answers.

36. In which of the following reactions conc. H2SO4 is used as an oxidising reagent?

(i) CaF2+ H2SO4 → CaSO4+ 2HF

(ii) 2HI + H2SO4 → I2 + SO2+ 2H2O

(iii) Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O

(iv) NaCl + H2SO4 → NaHSO4 + HCl

Solution:

Option (ii) and (iii) are the answers.

37. Which of the following statements are true?

(i) The only type of interactions between particles of noble gases is due to

weak dispersion forces.

(ii) Ionisation enthalpy of molecular oxygen is very close to that of xenon.

(iii) Hydrolysis of XeF6

is a redox reaction.

(iv) Xenon fluorides are not reactive.

Solution:

Option (i) and (ii) are the answers.

III. Short Answer Type

38. In the preparation of H2SO4 by Contact Process, why is SO3 not absorbed directly in water to form H2SO4?

Solution:

Dissolution of SO3 in water is highly exothermic. This leads to the formation of a mist of tiny droplets which are highly corrosive and they can even attack the lead pipelines (lead pipelines are used to cover the tower in contact process).

39. Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.

Solution:

NH3 + O2 →(Pt gauze) 4NO + 6H2O

Pt gauze reacts as a catalyst, which is added to increase the rate of reaction.

40. Write the structure of pyrophosphoric acid.

Solution:

41. PH3 forms bubbles when passed slowly in water but NH3 dissolves. Explain why?

Solution:

PH3 does not form hydrogen bonding with water. Therefore it is not soluble in water and it escapes as a gas and forms bubbles whereas ammonia forms hydrogen bonding and soluble in water.

42. In PCl5, phosphorus is in sp3d hybridised state but all its five bonds are not equivalent. Justify your answer with reason.

Solution:

The size of axial bonds is greater than the size of equatorial bonds to overcome repulsion because the three equatorial bonds cause more repulsion. Therefore two axial P-Cl bonds are longer and different from equatorial bonds.

43. Why is nitric oxide paramagnetic in gaseous state but the solid obtained on cooling it is diamagnetic?

Solution:

Nitric acid in the gaseous state exists in monomer form. It consists of only one unpaired electron therefore it is paramagnetic. In solid-state, it exists as a dimer (N2O2). There is no unpaired electron in its dimer form, therefore it is diamagnetic.

44. Give the reason to explain why ClF3 exists but FCl3 does not exist.

Solution:

Chlorine has vacant d orbitals hence it can show an oxidation state of +3. Fluorine has no d orbitals, it cannot show a positive oxidation state. Fluorine shows only -1 oxidation state. Therefore FCl3 does not exists.

45. Out of H2O and H2S, which one has a higher bond angle and why?

Solution:

H2O has higher bond angle than H2S because as we move from oxygen to sulphur the size of the central atom increases and electronegativity decreases due to which bond pair goes away from the central atom which results in a decrease in bond pair repulsion and hence bond angle decreases.

46. SF6 is known but SCl6 is not. Why?

Solution:

Fluorine is the strongest oxidizing agent and it can oxidize sulphur to its maximum oxidation state +6 to form SF6. Chlorine is not a good oxidizing agent, it cannot oxidize sulphur to its maximum oxidation state. Chlorine can oxidize sulphur to only +4 oxidation state. Hence it can form SCl4 but not SCl6.

47. On reaction with Cl2, phosphorus forms two types of halides ‘A’ and ‘B’. Halide A is a yellowish-white powder but halide ‘B’ is a colourless oily liquid. Identify A and B and write the formulas of their hydrolysis products.

Solution:

Halide A is PCl5 because it is a yellowish-white powder

Halide B is PCl3 because it is a colourless oily liquid.

PCl3 + 3H2O H3PO3 + 3HCl

PCl5 undergoes a violent hydrolysis

PCl5 + H2O POCl3 + 2HCl

PCl5 + 4H2O H3PO4 + 5HCl

48. In the ring test of NO3– ion, Fe2+ ion reduces nitrate ion to nitric oxide, which combines with Fe2+ (aq) ion to form the brown complex. Write the reactions involved in the formation of a brown ring.

Solution:

NO3^– + 3Fe²⁺ + 4H⁺ → NO + 3Fe2+ 2H2O

[Fe(H2O)6]SO4 + NO → [Fe(H2O)5NO]SO4

Thus the complex formed is brown.

49. Explain why the stability of oxoacids of chlorine increases in the order given below:

HClO< HClO2< HClO3< HClO4

Solution:

As the electronegativity of halogen decreases, the tendency of XO3 group ( X = halogens) to withdraw electrons of the O-H bond towards itself decreases and hence the acid strength of the perhalic acid decreases.

50. Explain why ozone is thermodynamically less stable than oxygen.

Solution:

Ozone is thermodynamically less stable because it decomposes into oxygen and this decomposition leads result in the liberation of heat, so its entropy is positive and free energy is negative.

51. P4O6 reacts with water according to equation P4O6 + 6H2O → 4H3PO3.

Calculate the volume of 0.1 M NaOH solution required to neutralise the acid formed by dissolving 1.1 g of P4O6 in H2O.

Solution:

P4O6 + 6H2O 4H3PO3

4H3PO3 + 8NaOH Na2HPO3 + 8H20

Overall reaction :

P4O6 + 8NaOH 4Na2HPO3 + 2H2O

Moles of P4O6 = 1.1/220 = 0.5

Acid formed by one mole of P4o6 requires = 8 mol

Acid formed by 0.005 mol of NaOH is present in 100mL solution

0.04 of NaOH is present in solution = 1000/0.1 *0.04 = 400mL

52. White phosphorus reacts with chlorine and the product hydrolyses in the presence of water. Calculate the mass of HCl obtained by the hydrolysis of the product formed by the reaction of 62 g of white phosphorus with chlorine in the presence of water.

Solution:

When white phosphorous reacts with chlorine:

P4 + 6Cl2 4PCl3

PCl3 + 3H2O H3PO3 + 4HCl ]*4

P4 +6Cl2 +12H2O 4H3PO3 +12HCl

Moles of white P= 62/124 = 0.5mol

1mol of white P4 produces HCl = 12mol

0.5 mol of white P4 will produce HCl = 12*0.8 = 6mol

Mass of HCl = 6*36.5 = 219.0g

53. Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in +3 oxidation state.

Solution:

There are three oxoacids of nitrogen.

Nitric acid(HNO3), Nitrous acid (HNO2), Hyponitrous acid (H2N2O1)

+ 3 oxidation is shown by HNO2, Therefore it undergoes disproportion reaction,

To calculate the oxidation state, consider the oxidation state of N is x.

3HNO2 HNO3 + 2NO +H2O

The oxidation state of nitrogen in HNO2 is +3

X + (+1) +2*(-2) = 0, x= +3

The oxidation state of nitrogen in HNO3 is +5

X + (+1) + 3*(-2) = 0, x= 5

The oxidation state of nitrogen in NO is +2

X + (-2) = 0, x =2

Therefore +3 oxidation state changes to +5 and +2 oxidation states.

54. Nitric acid forms an oxide of nitrogen on reaction with P4O10. Write the reaction involved. Also, write the resonating structures of the oxide of nitrogen formed.

Solution:

P4O10 + 4HNO3 4HPO3 + 2N2O5

White phosphorous is very reactive as compared to red phosphorous due to angular strain in white phosphorous.

55. Phosphorus has three allotropic forms — (i) white phosphorus (ii) red phosphorus and (iii) black phosphorus. Write the difference between white and red phosphorus on the basis of their structure and reactivity.

Solution:

1. White phosphorus

(i) It is soft waxy solid having garlic order

(ii) It is poisonous

(iii) Has low melting point and boiling point because P4 molecules are held together by weak van der Waal forces of attraction

2. Red Phosphorus

(i) It is hard, crystalline, odourless solid

(ii) It is non-poisonous

(iii) It has a high melting point because of its polymeric structure.

56. Give an example to show the effect of concentration of nitric acid on the formation of oxidation product.

Solution:

4Zn +10HNO3(dil) 4Zn(NO3)2 + NH4NO3 + 3H2O

4Zn +10HNO3(dil) 4Zn(NO3)2 + N2O + 5H2O

4Zn +4HNO3(conc.) Zn(NO3)2 + NO2 + 2H2O

57. PCl5 reacts with finely divided silver on heating and a white silver salt is obtained, which dissolves on adding excess aqueous NH3 solution. Write the reactions involved to explain what happens.

Solution:

PCl5 reacts with silver to form white silver salt(AgCl). Which than dissolves on adding excess aqueous NH3 to form a soluble complex

PCl5 + 2Ag 2AgCl(white ppt.) + PCl3

AgCl + 2NH3(aq) [Ag(NH3)]+Cl-

58. Phosphorus forms a number of oxoacids. Out of these oxoacidsphosphinicacid has strong reducing property. Write its structure and also write a reaction showing its reducing behaviour.

Solution:

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

2HgCl2 + H3PO2 + 2H2O 2Hg + H3PO4 + 4HCl

Class 12 Chemistry NCERT Exemplar for The p Block Elements

This chapter is one of the most important chapters for the CBSE Class 12 board examination. Every year, approximately 4 questions are asked from this chapter. To answer all questions related to the chapter, students are advised to solve the NCERT Exemplar Class 12 Chapter 7 The P Block Elements. The important topics discussed in the chapter are

Group 15 Elements
Dinitrogen
Ammonia
Oxides of Nitrogen
Nitric Acid
Phosphorus — Allotropic Forms
Phosphine
Phosphorus Halides
Oxoacids of Phosphorus
Group 16 Elements
Dioxygen
Simple Oxides
Ozone
Sulphur — Allotropic Forms
Sulphur Dioxide
Oxoacids of Sulphur
Sulphuric Acid
Group 17 Elements
Chlorine
Hydrogen Chloride
Oxoacids of Halogens
Interhalogen Compounds
Group 18 Elements

Why Opt for ANAND CLASSES (A School Of Competitions)

NCERT Exemplar solutions, provided at ANAND CLASSES (A School Of Competitions), are the result of comprehensive research. These solutions will help students understand the important topics from the exam point of view and help them crack the board exam with a good score. For NCERT Class 12 notes, study materials, NCERT solutions, exemplar questions, textbooks, previous years’ question papers and sample papers, visit ANAND CLASSES (A School Of Competitions) website or download ANAND CLASSES (A School Of Competitions) – The Learning App.

NCERT Class 12 Chemistry Exemplar Solutions for Chapter 7 The p Block Elements are essential study materials to ace the Class 12 board exam, as well as graduate entrance examinations. The NCERT Class 12 Chemistry Exemplar for Chapter 7 PDF will benefit students in solving the exercises given in the book and mastering the techniques of problem-solving. The NCERT Class 12 Chemistry Exemplar for Chapter 7 has exemplar questions given in the NCERT textbook, together with extra questions framed by the Chemistry experts at ANAND CLASSES (A School Of Competitions). This exemplar page also comprises problems on p block elements, important questions from previous years’ papers and sample papers.

Neeraj Anand, Param Anand

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 Scheme	Marks
Volumetric Analysis	08
Salt Analysis	08
Content Based Experiment	06
Project Work	04
Class record and viva	04
Total	30

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‐ , S^2‐, NO₂^‐ , SO₃^2‐, SO^2‐ , NO ^‐ , Cl^‐ , Br^‐, I‐, PO₄^3‐ , 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

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).

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.

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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