NCERT Exemplar Solutions-Thermodynamics for Class 11 Chemistry Chapter 6

NCERT Exemplar Solutions for Class 11 Chemistry Chapter 6 Thermodynamics

I. Multiple-choice Questions (Type-I)

1. Thermodynamics is not concerned about______.

(i) energy changes involved in a chemical reaction.

(ii) the extent to which a chemical reaction proceeds.

(iii) the rate at which a reaction proceeds.

(iv) the feasibility of a chemical reaction.

Solution:

Option (iii) is the answer.

2. Which of the following statements is correct?

(i) The presence of reacting species in a covered beaker is an example of

an open system.

(ii) There is an exchange of energy as well as a matter between the system

and the surroundings in a closed system.

(iii) The presence of reactants in a closed vessel made up of copper is an

example of a closed system.

(iv) The presence of reactants in a thermos flask or any other closed insulated

vessel is an example of a closed system.

Solution:

Option (iii) is the answer.

3. The state of a gas can be described by quoting the relationship between___.

(i) pressure, volume, temperature

(ii) temperature, amount, pressure

(iii) the amount, volume, temperature

(iv) pressure, volume, temperature, amount

Solution:

Option (iv) is the answer.

4. The volume of gas is reduced to half from its original volume. The specific

heat will be ______.

(i) reduce to half

(ii) be doubled

(iii) remain constant

(iv) increase four times

Solution:

Option (iii) is the answer.

5. During complete combustion of one mole of butane, 2658 kJ of heat is released.

The thermochemical reaction for above change is

(i) 2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l) ∆cH = –2658.0 kJ mol–1

(ii) C4H10(g) +13/2 O2 (g) → 4CO2 (g) + 5H2O (g) ∆cH = –1329.0 kJ mol–1

(iii) C4H10(g) +13/2 O2 (g) → 4CO2 (g) + 5H2O (l) ∆cH = –2658.0 kJ mol–1

(iv) C4H10 (g) +13/2 O2 (g) → 4CO2 (g) + 5H2O (l) ∆cH = +2658.0 kJ mol–1

Solution:

Option (iii) is the answer.

6. ∆fUᶱ of formation of CH4 (g) at a certain temperature is –393 kJ mol–1. The

value of ∆ fHᶱ is

(i) zero

(ii) < ∆f Uᶱ

(iii) > ∆f Uᶱ

(iv) equal to ∆f Uᶱ

Solution;

Option (ii) is the answer.

7. In an adiabatic process, no transfer of heat takes place between system and

surroundings. Choose the correct option for free expansion of an ideal gas

under adiabatic condition from the following.

(i) q = 0, ∆T ≠ 0, w = 0

(ii) q ≠ 0, ∆T = 0, w = 0

(iii) q = 0, ∆T = 0, w = 0

(iv) q = 0, ∆T < 0, w ≠ 0

Solution:

Option (iii) is the answer.

8. The pressure-volume work for an ideal gas can be calculated by using the expression w= ʃPexdv. The work can also be calculated from the pV– a plot by using the area under the curve within the specified limits. When an ideal gas is compressed (a) reversibly or (b) irreversibly from volume Vi

to Vf. choose the correct option.

(i) w (reversible) = w (irreversible)

(ii) w (reversible) < w (irreversible)

(iii) w (reversible) > w (irreversible)

(iv) w (reversible) = w (irreversible) + pex.∆V

Solution:

Option (ii) is the answer.

9. The entropy change can be calculated by using the expression ∆S = qrev/T

When water freezes in a glass beaker, choose the correct statement amongst

the following :

(i) ∆S (system) decreases but ∆S (surroundings) remains the same.

(ii) ∆S (system) increases but ∆S (surroundings) decreases.

(iii) ∆S (system) decreases but ∆S (surroundings) increases.

(iv) ∆S (system) decreases and ∆S (surroundings) also decreases.

Solution:

Option (iii) is the answer.

10. On the basis of thermochemical equations (a), (b) and (c), find out which of the

algebraic relationships given in options (i) to (iv) is correct.

(a) C (graphite) + O2 (g) → CO2 (g) ; ∆rH = x kJ mol–1

(b) C (graphite) +12 O2 (g) → CO (g) ; ∆rH = y kJ mol–1

(c) CO (g) +12 O2 (g) → CO2 (g) ; ∆rH = z kJ mol–1

(i) z = x + y

(ii) x = y – z

(iii) x = y + z

(iv) y = 2z – x

Solution:

Option (iii) is the answer.

11. Consider the reactions given below. On the basis of these reactions find out

which of the algebraic relations given in options (i) to (iv) is correct?

(a) C (g) + 4 H (g) → CH4 (g); ∆rH = x kJ mol–1

(b) C (graphite,s) + 2H2 (g) → CH4 (g); ∆rH = y kJ mol–1

(i) x = y

(ii) x = 2y

(iii) x > y

(iv) x < y

Solution:

Option (iii) is the answer.

12. The enthalpies of elements in their standard states are taken as zero. The

enthalpy of formation of a compound

(i) is always negative

(ii) is always positive

(iii) maybe positive or negative

(iv) is never negative

Solution:

Option (iii) is the answer.

13. Enthalpy of sublimation of a substance is equal to

(i) enthalpy of fusion + enthalpy of vapourisation

(ii) enthalpy of fusion

(iii) enthalpy of vapourisation

(iv) twice the enthalpy of vapourisation

Solution:

Option (i) is the answer.

14. Which of the following is not correct?

(i) ∆G is zero for a reversible reaction

(ii) ∆G is positive for a spontaneous reaction

(iii) ∆G is negative for a spontaneous reaction

(iv) ∆G is positive for a non-spontaneous reaction

Solution:

Option (ii) is the answer.

II. Multiple Choice Questions (Type-II)

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

15. Thermodynamics mainly deals with

(i) interrelation of various forms of energy and their transformation from

one form to another.

(ii) energy changes in the processes which depend only on initial and final

states of the microscopic systems containing a few molecules.

(iii) how and at what rate these energy transformations are carried out?

(iv) the system in an equilibrium state or moving from one equilibrium state to

another equilibrium state.

Solution:

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

16. In an exothermic reaction, heat is evolved, and the system loses heat to the

surrounding. For such a system

(i) qp will be negative

(ii) ∆rH will be negative

(iii) qp will be positive

(iv) ∆rH will be positive

Solution:

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

17. Spontaneity means having the potential to proceed without the assistance

of an external agency. The processes which occur spontaneously are

(i) flow of heat from colder to warmer body.

(ii) gas in a container contracting into one corner.

(iii) gas expanding to fill the available volume.

(iv) burning carbon in oxygen to give carbon dioxide.

Solution:

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

18. For an ideal gas, the work of reversible expansion under isothermal condition

can be calculated by using the expression w = – nRT ln Vf/Vi

A sample containing 1.0 mol of an ideal gas is expanded isothermally and

reversibly to ten times of its original volume, in two separate experiments.

The expansion is carried out at 300 K and 600 K, respectively. Choose the

correct option.

(i) Work done at 600 K is 20 times the work done at 300 K.

(ii) Work done at 300 K is twice the work done at 600 K.

(iii) Work done at 600 K is twice the work done at 300 K.

(iv) ∆U = 0 in both cases.

Solution:

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

19. Consider the following reaction between zinc and oxygen and choose the correct

options out of the options given below :

2 Zn (s) + O2 (g) → 2 ZnO (s) ; ∆H = – 693.8 kJ mol–1(i) The enthalpy of two moles of ZnO is less than the total enthalpy of two

moles of Zn and one mole of oxygen by 693.8 kJ.

(ii) The enthalpy of two moles of ZnO is more than the total enthalpy of two

moles of Zn and one mole of oxygen by 693.8 kJ.

(iii) 693.8 kJ mol–1 energy is evolved in the reaction.

(iv) 693.8 kJ mol–1 energy is absorbed in the reaction.

Solution:

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

III. Short Answer Type

20. 18.0 g of water completely vapourises at 100°C and 1 bar pressure and the enthalpy change in the process is 40.79 kJ mol–1. What will be the enthalpy change for vapourising two moles of water under the same conditions? What is the standard enthalpy of vapourisation for water?

Solution:

Enthalpy change of vapourisation for 1 mole = 40.79 kJ mol–1 enthalpy change of vapourisation for 2 moles of water = (40.79 × 2) = 81.58kJ mol–1

for water ∆Hvapourisation, ⁰ will be equal to =40.79 kJ mol–1

21. One mole of acetone requires less heat to vaporise than 1 mol of water. Which of the two liquids has a higher enthalpy of vapourisation?

Solution:

Among the two liquids, water has a higher enthalpy of vapourisation (consuming higher heat energy).

Therefore, ∆Hvapourisation (water) > ∆Hvapourisation (acetone).

22. Standard molar enthalpy of formation, Δf HΘis just a special case of enthalpy of reaction, Δr HΘ. Is the Δr HΘfor the following reaction the same as Δf HΘ? Give the reason for your answer.

CaO(s) + CO2(g) → CaCO3(s) ; ΔfHΘ = –178.3 kJ mol–1

Solution:

The given reaction CaO(s) + CO2(g) →CaCO3(s) indicates that it is occurring in the standard form of 1 mole of each substance. And the molar enthalpy of formation ΔfHΘ = –178.3 kJ mol–1 Given for CaCO3 is also showing the standard conditions.

So,ΔfHΘ = –178.3 kJ mol–1 = Δr HΘ .

23. The value of ΔfHΘfor NH3 is – 91.8 kJ mol–1. Calculate the enthalpy change for the following reaction :

2NH3(g) → N2(g) + 3H2(g)

Solution:

Enthalpy change of a reaction is calculated as

: Σbond enthalpy of reactants- Σbond enthalpy of products

for the decomposition 2NH3(g) →N2(g) + 3H2(g) ΔrHΘ will be =

– (– 91.8 kJ mol–1 ) = + 91.8 kJ mol–1

for 2 moles of NH3 enthalpy change of the reaction will be ΔrH = (2 X 91.8 ) = 183.6 kJ mol–1 .

24. Enthalpy is an extensive property. In general, if the enthalpy of an overall reaction A→B along one route is Δr H and Δr H1, ΔrH2, ΔrH3 ….. represent enthalpies of intermediate reactions leading to product B. What will be the relation between ΔrH for overall reaction and ΔrH1, ΔrH2….. etc. for intermediate reactions.

Solution:

For the reaction, A→B the formation of B goes through several intermediate reactions with different enthalpy values Δr H1, ΔrH2, ΔrH3….., and the overall enthalpy change is Δr H.

25. The enthalpy of atomisation for the reaction CH4(g)→ C(g) + 4H (g) is 1665 kJ mol–1. What is the bond energy of the C–H bond?

Solution:

For 1 C-H bond, the bond energy will be equal to 1/4 that of the enthalpy of atomisation

= (1665/4) = 416.25 kJ mol–1.

26. Use the following data to calculate Δlattice HΘfor NaBr.

Δsub HΘfor sodium metal = 108.4 kJ mol–1

Ionization enthalpy of sodium = 496 kJ mol–1

Electron gain enthalpy of bromine = – 325 kJ mol–1

Bond dissociation enthalpy of bromine = 192 kJ mol–1

Δf HΘfor NaBr (s) = – 360.1 kJ mol–1

Solution:

Sublimation of the metal(ΔsubHΘ) →Ionization of the metal (ΔiHΘ) →Dissociation of the non-metal (ΔdissHΘ) →Gain of electrons by the non-metal(ΔegHΘ)

Δf HΘ =Δsub HΘ+Δi HΘ+1/2 dissHΘ + ΔegHΘ+ ΔlattticeHΘ

To calculate the lattice enthalpy of NaBr,

Na(s) → Na(g) ; ΔsubHΘ =108.4 kJ mol–1 (i)

Na→ Na+ + e- ; ΔiHΘ = 496 kJ mol–1 (ii)

1/2 Br2→ Br ; 1/2 ΔdissHΘ = ( ) = 96 kJ mol–1 (iii)

Br + e-→ Br- ;ΔegHΘ= – 325 kJ mol–1 (iv)

enthalpy of formation Δf HΘ = processes (i) + (ii) + (ii) + (iv)

Δlattice HΘ = Δf HΘ – ΔsubHΘ – ΔiHΘ – 1/2 ΔdissHΘ –ΔegHΘ

= -735.5kjmol-1.

27. Given that ΔH = 0 for mixing of two gases. Explain whether the diffusion of these gases into each other in a closed container is a spontaneous process or not.

Solution:

A negative ∆G means the reaction will be the spontaneous included contribution of the other factors like enthalpy(H) and entropy(S).

∆G= ∆H – T∆S

∆H being 0,

∆G will be negative (as the positive value of ∆S will give a more negative T∆S)

∆H=0 ; ∆G= -T∆S= negative.

28. Heat has a randomising influence on a system, and temperature is the measure of the average chaotic motion of particles in the system. Write the mathematical relation which relates these three parameters.

Solution:

The mathematical relation which relates these three parameters is ΔS = qrev/T

where ΔS is the change in entropy and T stands for temperature.

29. Increase in enthalpy of the surroundings is equal to the decrease in enthalpy of the system. Will the temperature of the system and surroundings be the same when they are in thermal equilibrium?

Solution:

As thermal equilibrium obeys the zeroth law of thermodynamics, temperature of system and surroundings will be the same when they are in thermal equilibrium.

30. As thermal equilibrium obeys the zeroth law of thermodynamics, temperature of system and surroundings will be the same when they are in thermal equilibrium.

Solution:

For the given reaction N2O4 (g) ⇋2NO2 (g) the value of Kp = 0.98.

Hence, ∆rG⁰ = – RT ln(0.98)

Since ln(0.98) has a negative value, the value of ∆rG⁰ becomes positive. Therefore, the reaction is non-spontaneous.

31. A sample of 1.0 mol of a monoatomic ideal gas is taken through a cyclic

process of expansion and compression as shown in Fig. 6.1. What will be the

value of ∆H for the cycle as a whole?

I. Multiple-choice Questions (Type-I)

Solution:

In the following cyclic ( 1 → 2 →3 →1 ) process the initial and final point is the same (i.e. 1). Hence the enthalpy change or ∆H= 0, in other words, there will be no change in enthalpy.

32. The standard molar entropy of H2O (l ) is 70 J K–1 mol–1. Will the standard molar entropy of H2O(s) be more or less than 70 J K–1 mol–1?

Solution:

The entropy of H2O(s)

33. Identify the state functions and path functions out of the following :

enthalpy, entropy, heat, temperature, work, and free energy.

Solution:

State functions: enthalpy, entropy, temperature and free energy.

Path functions: Heat and work

34. The molar enthalpy of vapourisation of acetone is less than that of water. Why?

Solution:

Water has strong hydrogen bonds and the high polarity also adds up, resulting in it boiling at higher temperatures. Hence water has a higher molar enthalpy than acetone.

35. Which quantity out of ΔrG and ΔrGΘwill be zero at equilibrium?

Solution:

At equilibrium ΔrGΘ = – RT lnK .

ΔrGΘ can only be 0 when the value of K is =1. So, for all the other K values ΔrGΘ cannot be zero.

36. Predict the change in internal energy for an isolated system at constant volume.

Solution:

For an isolated system q=0 and w=0

And according to 1st law of thermodynamics: ∆U= q + w (U=internal energy)

Therefore, change in internal energy for an isolated system ∆U = 0.

37. Although heat is a path function but heats absorbed by the system under certain specific conditions is independent of path. What are those conditions? Explain.

Solution;

Heat is independent of the path under 2 conditions:

1. When the volume of the system is kept constant-

By 1st law of thermodynamics:

q = ΔU + (-w)

and -w = pΔV

Therefore , q = ΔU + pΔV

ΔV = 0 (at constant volume)

Hence, qv = ΔU + 0 = ΔU= change in internal energy

2. When the pressure of the system is kept constant –

At constant pressure, qp= ΔU + pΔV

But , ΔU + pΔV = ∆H

Therefore, qp = ∆H = change in enthalpy.

38. Expansion of gas in a vacuum is called free expansion. Calculate the work is done and the change in internal energy when 1 litre of an ideal gas expands isothermally into a vacuum until its total volume is 5 litre.

Solution:

Work done in vacuum is calculated by :

-w = Text (Vinitial – Vfinal )

Pext= 0

–w = 0x(5-1) = 0.

For isothermal expansion q=o

q= ∆U + (-w)

Hence ∆U will be 0.

39. Heat capacity (Cp) is an extensive property but specific heat (c) is an intensive property. What will be the relation between Cp and c for 1 mol of water?

Solution;

1 mole of water = 18 g.

Hence, for water, Heat capacity = 18 × specific heat.

i.e. Cp = 18 × C .

40. The difference between CP and CV can be derived using the empirical relation H = U + PV. Calculate the difference between CP and CV for 10 moles of an ideal gas.

Solution:

For an ideal gas, the difference between these two is CP – CV = nR, the universal gas constant and where n= no. of moles

Hence for 10 moles of an ideal gas CP – CV = 10 R

CP – CV = 10 × 8.314 J

= 83.14 J

41. If the combustion of 1g of graphite produces 20.7 kJ of heat, what will be molar enthalpy change? Give the significance of the sign also.

Solution:

The heat of combustion ∆Hc of graphite (i.e. carbon) is given as = 20.7 kJ for 1g of graphite (C).

1 mole of Carbon = 12 g

Hence the molar enthalpy change (enthalpy for 1 mole )

= (20.7 × 12 )= 248.4 KJ mol-1

Since the heat is evolved, the actual molar enthalpy change

= -248.4 KJ mol-1

In combustion reactions, heat is always evolved i.e. it is an exothermic reaction. Hence the sign of ∆H for the reaction will always be negative (for the process to occur).

42. The net enthalpy change of a reaction is the amount of energy required to break all the bonds in reactant molecules minus the amount of energy required to form all the bonds in the product molecules. What will be the enthalpy change for the following reaction?

H2(g) + Br2(g) → 2HBr(g)

Given that Bond energy of H2, Br2 and HBr is 435 kJ mol–1, 192 kJ mol–1 and 368 kJ mol–1 respectively.

Solution:

For the reaction

H2(g) + Br2(g) →2HBr(g)

Enthalpy change

= (Bond energy of H-H bond + Br-Br bond) – (2 × bond energy of H-Br)

= (435 + 192) kJ mol–1 – (2 × 368) kJ mol–1

= -109 kJ mol–1

43. The enthalpy of vapourisation of CCl4 is 30.5 kJ mol–1. Calculate the heat required for the vapourisation of 284 g of CCl4 at constant pressure. (Molar mass of CCl4 = 154 g mol–1).

Solution:

The enthalpy of vapourisation is given for 1 mole of CCl4 = 30.5 kJ mol–1

Hence, for 284 g, it will be = (mole no. × 30.5) kJ

Molar mass of CCl4 = 154 g mol–1 that means 154 g = 1 mole.

Therefore , 284 g = (284g/154gmol-1)= 1.84 mole.

Hence the heat required for the vapourisation of 284 g of CCl4 at constant pressure = (1.84 mol ×30.5 KJ mol-1) kJ

=56.12 KJ

44. The enthalpy of reaction for the reaction :

2H2(g) + O2(g) → 2H2O(l) is ∆HrΘ = – 572 kJ mol–1

What will be standard enthalpy of formation of H2O (l)?

Solution:

For the given reaction : 2H2(g) + O2(g) →2H2O(l)

the standard enthalpy of reaction is ∆HrΘ = – 572 kJ mol–1 , so the half of ∆HrΘ will be the standard molar enthalpy of formation ;

ΔfHΘ = 1/2 × ∆HrΘ = (-572/2) = -286 kJ mol–1 .

45. What will be the work done on an ideal gas enclosed in a cylinder, when it is compressed by constant external pressure, pext in a single step as shown in Fig? 6.2. Explain graphically.

I. Multiple-choice Questions (Type-I)

Solution:

From this graph, we can obtain the be the work done on the ideal gas enclosed in the cylinder in 1 step: the area covered by P-V graph (shaded region) is the actual value of the work done is:

= length × breadth = pext ∆V = AVI (or BVII ) × (VI – VII )

46. How will you calculate work done on an ideal gas in a compression, when a change in pressure is carried out in infinite steps?

Solution:

When an ideal gas in a compression, where the change in pressure is carried out in infinite steps i.e. through a reversible process, the work done can be calculated only through the observation of pressure vs volume plot of the process.

I. Multiple-choice Questions (Type-I)

The shaded area in the above graph represents the work done in the process, by calculating the area covered we can calculate the work done.

47. Represent the potential energy/enthalpy change in

the following processes graphically.

(a) Throwing a stone from the ground to the roof.

(b) 1/2 H2(g) + 1/2 Cl2(g) ⇋ HCl(g) ΔrHΘ = –92.32 kJ mol–1

In which of the processes potential energy/enthalpy change is contributing factor to the spontaneity?

Solution:

I. Multiple-choice Questions (Type-I)

Amongst these two processes, in the process or reaction (b) the potential energy/enthalpy change is contributing factor to the spontaneity.

48. Enthalpy diagram for a particular reaction is given in Fig. 6.3. Is it possible to decide the spontaneity of a reaction from the given diagram? Explain.

I. Multiple-choice Questions (Type-I)

Solution:

From the given enthalpy diagram, it can be said the change in enthalpy ∆H is positive for the reaction, i.e. it will be endothermic. But when it comes to the spontaneity of a reaction, enthalpy is just a factor and there are other important factors like entropy, Gibb’s free energy also taken into consideration. Hence enthalpy alone cannot determine the spontaneity of a reaction; one must have a loo to the other contributing factors also.

49. 1.0 mol of a monoatomic ideal gas is expanded from state (1) to state (2) as shown in Fig. 6.4. Calculate the work done for the expansion of gas from state (1) to state (2) at 298 K.

Solution:

I. Multiple-choice Questions (Type-I)

W= – 2.303nRT log (p1/p2)

= – 2.303 × 1 mol × 8.314 J mol-1 K-1 × 298 K × log2

=- 2.303 × 8.314 × 298 × 0.3010 J

= -1717.46 J

50. An ideal gas is allowed to expand against a constant pressure of 2 bar from 10 L to 50 L in one step. Calculate the amount of work done by the gas. If the same expansion were carried out reversibly, will the work is done be higher or lower than the earlier case? (Given that 1 L bar = 100J)

Solution:

Amount of work done = -pext ∆V

= – 2 bar × (50 – 10 ) L = – 80 L bar.

Now, it is given that 1 L bar = 100 J

So , -80 L bar = (-80 × 100) = -8000 J

= -8 KJ is the amount of work done in the above process.

If it is reversible, then the internal pressure will be larger than the external pressure. So the work done will own a higher value.


Subtopics Covered in Class 11 Chemistry Chapter 6 Thermodynamics

  1. Thermodynamic Terms
    1. The System and the Surroundings
    2. Types of the System
    3. The State of the System
    4. Internal Energy as a State Function
  2. Applications
    1. Work
    2. Enthalpy, H
  3. Measurement of Du and Dh: Calorimetry
  4. Enthalpy Change, Drh of a Reaction – Reaction Enthalpy
  5. Enthalpies for Different Types of Reactions
  6. Spontaneity
  7. Gibbs Energy Change and Equilibrium.

Chapter 6, Thermodynamics, is one of the important chapters in Class 11 Chemistry that lays a strong foundation for all your future endeavours. It is very essential to grasp the Thermodynamics concept thoroughly to avoid difficulty in higher studies. In order to make students learn Chemistry topics easily, ANAND CLASSES (A School Of Competitions) provides special videos, animations, and exercises that will not only help students understand the topic but also help in memorising the topic for a long period of time.

Frequently Asked Questions on NCERT Exemplar Solutions for Class 11 Chemistry Chapter 6

Q1

Why should I choose ANAND CLASSES (A School Of Competitions) NCERT Exemplar Solutions for Class 11 Chemistry Chapter 6?

Chapter 6 is considered to be one of the important chapters in the Class 11 Chemistry syllabus. The basic concepts of Thermodynamics are discussed in brief in this chapter. Learning this chapter plays an important role in the study of students who opt for Chemistry at their higher level of education. We, at ANAND CLASSES (A School Of Competitions), provide the students with the best quality solutions so that the concepts can be understood effortlessly. The subject-matter experts created the solutions with the aim of helping students to score well in the annual exam.

Q2

What can I learn in Chapter 6 of NCERT Exemplar Solutions for Class 11 Chemistry?

Chapter 6 of NCERT Exemplar Solutions for Class 11 Chemistry deals with Thermodynamics terms and their applications. Students can also obtain in-depth knowledge about the measurement of Du and Dh: calorimetry and enthalpy change. To get a clear idea about the important concepts and score good marks in the Class 11 Chemistry exam, students can refer to the NCERT Exemplar Solutions available at ANAND CLASSES (A School Of Competitions). By practising these solutions on a regular basis, the comprehensive explanations provided will help students to perform well in the annual exam.

Q3

List out the topics/subtopics covered in Chapter 6 of NCERT Exemplar Solutions for Class 11 Chemistry.

The topics/subtopics covered in Chapter 6 of NCERT Exemplar Solutions for Class 11 Chemistry are listed below:
1. Thermodynamic Terms
a. The System and the Surroundings
b. Types of the System
c. The State of the System
d. Internal Energy as a State Function
2. Applications
a. Work
b. Enthalpy
3. Measurement of Du and Dh: Calorimetry
4. Enthalpy Change, Drh of a Reaction – Reaction Enthalpy
5. Enthalpies for Different Types of Reactions
6. Spontaneity
7. Gibbs Energy Change and Equilibrium

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.