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Chapters
2: Structure of Atom
3: Classification of Elements and Periodicity in Properties
4: Chemical Bonding and Molecular Structure
5: States of Matter
6: Thermodynamics
▶ 7: Equilibrium
8: Redox Reactions
9: Hydrogen
10: The s-block Elements
11: The p-block Elements
12: Organic Chemistry Some Basic Principles and Techniques
13: Hydrocarbons
14: Environmental Chemistry
![NCERT Exemplar solutions for Chemistry [English] Class 11 chapter 7 - Equilibrium - Shaalaa.com](/images/chemistry-english-class-11_6:5f2b1b2038084cf381bfa42c826a928c.jpg "NCERT Exemplar solutions for Chemistry [English] Class 11 chapter 7 - Equilibrium")
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Solutions for Chapter 7: Equilibrium
Below listed, you can find solutions for Chapter 7 of CBSE NCERT Exemplar for Chemistry [English] Class 11.
NCERT Exemplar solutions for Chemistry [English] Class 11 7 Equilibrium Multiple Choice Questions (Type - I) [Pages 86 - 96]
We know that the relationship between Kc and Kp is Kp = Kc (RT)∆n What would be the value of ∆n for the reaction \[\ce{NH4Cl (s) ⇌ NH3 (g) + HCl (g)}\]
1
0.5
1.5
2
For the reaction \[\ce{H2 (g) + I2 (g) ⇌ 2HI (g)}\], the standard free energy is ∆GΘ > 0. The equilibrium constant (K ) would be ______.
K = 0
K > 1
K = 1
K < 1
Which of the following is not a general characteristic of equilibria involving physical processes?
(i) Equilibrium is possible only in a closed system at a given temperature.
(ii) All measurable properties of the system remain constant.
(iii) All the physical processes stop at equilibrium.
(iv) The opposing processes occur at the same rate and there is dynamic but stable condition.
\[\ce{PCl5, PCl3 and Cl2}\] are at equilibrium at 500 K in a closed container and their concentrations are 0.8 × 10–3 mol L–1, 1.2 × 10–3 mol L–1 and 1.2 × 10–3 mol L–1 respectively. The value of Kc for the reaction \[\ce{PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)}\] will be ______.
1.8 × 103 mol L–1
1.8 × 10–3
1.8 × 10–3 L mol–1
0.55 × 104
Which of the following statements is incorrect?
In equilibrium mixture of ice and water kept in perfectly insulated flask mass of ice and water does not change with time.
The intensity of red colour increases when oxalic acid is added to a solution containing iron (III) nitrate and potassium thiocyanate.
On addition of catalyst the equilibrium constant value is not affected.
Equilibrium constant for a reaction with negative ∆H value decreases as the temperature increases.
When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the correct answer.
\[\ce{\underset{(pink)}{[Co(H2O)6]^{3+}} (aq) + 4Cl- (qa) ⇌ \underset{(blue)}{[CoCl4]^{2-}} (aq) + 6H2O (l)}\]
∆H > 0 for the reaction
∆H < 0 for the reaction
∆H = 0 for the reaction
The sign of ∆H cannot be predicted on the basis of this information.
The pH of neutral water at 25°C is 7.0. As the temperature increases, ionisation of water increases, however, the concentration of \[\ce{H+}\] ions and \[\ce{OH-}\] ions are equal. What will be the pH of pure water at 60°C?
Equal to 7.0
Greater than 7.0
Less than 7.0
Equal to zero
The ionisation constant of an acid, Ka, is the measure of strength of an acid. The Ka values of acetic acid, hypochlorous acid and formic acid are 1.74 × 10–5, 3.0 × 10–8 and 1.8 × 10–4 respectively. Which of the following orders of pH of 0.1 mol dm–3 solutions of these acids is correct?
Acetic acid > Hypochlorous acid > Formic acid
Hypochlorous acid > Acetic acid > Formic acid
Formic acid > Hypochlorous acid > Acetic acid
Formic acid > Acetic acid > Hypochlorous acid
\[\ce{K_{a_1}, K_{a_2}}\] and \[\ce{K_{a_3}}\] are the respective ionisation constants for the following reactions.
\[\ce{H2S ⇌ H^{+} + Hs-}\]
\[\ce{Hs- ⇌ H^{+} + S^{2-}}\]
\[\ce{H2S ⇌ 2H^{+} + S^{2-}}\]
The correct relationship between \[\ce{K_{a_1}, K_{a_2}}\] and \[\ce{K_{a_3}}\] is ______.
\[\ce{K_{a_3} = K_{a_1} × K_{a_2}}\]
\[\ce{K_{a_3} = K_{a_1} + K_{a_2}}\]
\[\ce{K_{a_3} = K_{a_1} - K_{a_2}}\]
\[\ce{K_{a_3} = K_{a_1} / K_{a_2}}\]
Acidity of \[\ce{BF3}\] can be explained on the basis of which of the following concepts?
Arrhenius concept
Bronsted Lowry concept
Lewis concept
Bronsted Lowry as well as Lewis concept.
Which of the following will produce a buffer solution when mixed in equal volumes?
0.1 mol dm–3 \[\ce{NH4OH}\] and 0.1 mol dm–3 \[\ce{HCl}\]
0.05 mol dm–3 \[\ce{NH4OH}\] and 0.1 mol dm–3 \[\ce{HCl}\]
0.1 mol dm–3 \[\ce{NH4OH}\] and 0.05 mol dm–3 \[\ce{HCl}\]
0.1 mol dm–3 \[\ce{CH4COONa}\] and 0.1 mol dm–3 \[\ce{NaOH}\]
In which of the following solvents is silver chloride most soluble?
0.1 mol dm–3 \[\ce{AgNO3}\] solution
0.1 mol dm–3 \[\ce{HCl}\] solution
\[\ce{H2O}\]
Aqueous ammonia
What will be the value of pH of 0.01 mol dm–3 \[\ce{CH3COOH}\] (Ka = 1.74 × 10–5)?
3.4
3.6
3.9
3.0
\[\ce{K_a}\] for \[\ce{CH3COOH}\] is 1.8 × 10–5 and \[\ce{K_b}\] for \[\ce{NH4OH}\] is 1.8 × 10–5 . The \[\ce{pH}\] of ammonium acetate will be ______.
7.005
4.75
7.0
Between 6 and 7
Which of the following options will be correct for the stage of half completion of the reaction A ⇌ B.
∆GΘ = 0
∆GΘ > 0
∆GΘ < 0
∆GΘ = – RT ln 2
On increasing the pressure, in which direction will the gas phase reaction proceed to re-establish equilibrium, is predicted by applying the Le Chatelier’s principle. Consider the reaction.
\[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g)}\]
Which of the following is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?
K will remain same.
K will decrease.
K will increase.
K will increase initially and decrease when pressure is very high.
What will be the correct order of vapour pressure of water, acetone and ether at 30°C. Given that among these compounds, water has maximum boiling point and ether has minimum boiling point?
Water < ether < acetone
Water < acetone < ether
Ether < acetone < water
Acetone < ether < water
At 500 K, equilibrium constant, \[\ce{K_c}\], for the following reaction is 5.
\[\ce{1/2 H2 (g) + 1/2 I2 (g) ⇌ HI (g)}\]
What would be the equilibrium constant \[\ce{K_c}\] for the reaction
\[\ce{2HI (g) ⇌ H2 (g) + I2 (g)}\]
0.04
0.4
25
2.5
In which of the following reactions, the equilibrium remains unaffected on addition of small amount of argon at constant volume?
\[\ce{H2 (g) + I2 (g) ⇌ 2HI (g)}\]
\[\ce{PCl5 (g) ⇌ PCl3 (g) + CL2 (g)}\]
\[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g)}\]
The equilibrium will remain unaffected in all the three cases.
For the reaction \[\ce{N2O4 (g) ⇌ 2NO2 (g)}\], the value of K is 50 at 400 K and 1700 at 500 K. Which of the following options is correct?
(i) The reaction is endothermic.
(ii) The reaction is exothermic.
T
(iv) The entropy of the system increases.
At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following term defines this temperature?
(i) Normal melting point
(ii) Equilibrium temperature
(iii) Boiling point
(iv) Freezing point
The ionisation of hydrochloric in water is given below:
\[\ce{HCl (aq) + H2O (l) ⇌ H3O+ (aq) + Cl- (aq)}\]
Label two conjugate acid-base pairs in this ionisation.
The aqueous solution of sugar does not conduct electricity. However, when sodium chloride is added to water, it conducts electricity. How will you explain this statement on the basis of ionisation and how is it affected by concentration of sodium chloride?
\[\ce{BF3}\] does not have proton but still acts as an acid and reacts with \[\ce{NH3}\]. Why is it so? What type of bond is formed between the two?
Ionisation constant of a weak base MOH, is given by the expression
`K_b = ([M^+][OH^-])/([MOH])`
Values of ionisation constant of some weak bases at a particular temperature are given below:
| Base | Dimethylamine | Urea | Pyridine | Ammonia |
| \[\ce{K_b}\] | 5.4 × 10–4 | 1.3 × 10–14 | 1.77 × 10–9 | 1.77 × 10–5 |
Arrange the bases in decreasing order of the extent of their ionisation at equilibrium. Which of the above base is the strongest?
Conjugate acid of a weak base is always stronger. What will be the decreasing order of basic strength of the following conjugate bases?
\[\ce{OH-, RO-, CH3COO-, Cl-}\]
Arrange the following in increasing order of \[\ce{pH}\].
\[\ce{KNO3 (aq), CH3COONa (aq), NH4Cl (aq), C6H5COONH4 (aq)}\]
The value of \[\ce{K_c}\] for the reaction \[\ce{2HI (g) ⇌ H2 (g) + I2 (g)}\] is 1 × 10–4 At a given time, the composition of reaction mixture is \[\ce{[HI]}\] = 2 × 10–5 mol, \[\ce{[HI]}\] = 1 × 10–5 mol and \[\ce{[I2]}\] = 1 × 10–5 mol In which direction will the reaction proceed?
On the basis of the equation \[\ce{pH}\] = – log \[\ce{[H+]}\], the \[\ce{pH}\] of 10–8 mol dm–3 solution of \[\ce{HCl}\] should be 8. However, it is observed to be less than 7.0. Explain the reason.
\[\ce{pH}\] of a solution of a strong acid is 5.0. What will be the \[\ce{pH}\] of the solution obtained after diluting the given solution a 100 times?
A sparingly soluble salt gets precipitated only when the product of concentration of its ions in the solution (Qsp) becomes greater than its solubility product. If the solubility of \[\ce{BaSO4}\] in water is 8 × 10–4 mol dm–3. Calculate its solubility in 0.01 mol dm–3 of \[\ce{H2SO4}\].
\[\ce{pH}\] of 0.08 mol dm–3 \[\ce{HOCl}\] solution is 2.85. Calculate its ionisation constant
Calculate the \[\ce{pH}\] of a solution formed by mixing equal volumes of two solutions A and B of a strong acid having \[\ce{pH}\] = 6 and \[\ce{pH}\] = 4 respectively.
The solubility product of \[\ce{Al(OH)3}\] is 2.7 × 10–11. Calculate its solubility in gL–1 and also find out pH of this solution. (Atomic mass of \[\ce{Al = 27 u}\]).
Calculate the volume of water required to dissolve 0.1 g lead (II) chloride to get a saturated solution. \[\ce{(K_{sp} of PbCl2}\] = 3.2 × 10–8, atomic mass of \[\ce{Pb = 207 u}\]).
A reaction between ammonia and boron trifluoride is given below: \[\ce{NH3 + BF3 -> H3N : BF3}\] Identify the acid and base in this reaction. Which theory explains it? What is the hybridisation of B and N in the reactants?
Following data is given for the reaction: \[\ce{CaCO3 (S) -> CaO (s) + CO2 (g)}\]
\[\ce{∆_fH^Θ [CaO(s)] = - 635.1 kJ mo^{-1}}\]
\[\ce{∆_fH^Θ [CO2(g)] = - 393.5 kJ mol^{-1}}\]
\[\ce{∆_fH^Θ [CaCO3(s)] = - 1206.9 kJ mol^{-1}}\]
Predict the effect of temperature on the equilibrium constant of the above reaction.
Match the following equilibria with the corresponding condition:
| Column I | Column II |
| (i) Liquid ⇌ Vapour | (a) Saturated solution |
| (ii) Solid ⇌ Liquid | (b) Boiling point |
| (iii) Solid ⇌ Vapour | (c) Sublimation point |
| (iv) Solute (s) ⇌ Solute (solution) | (d) Melting point Unsaturated solution |
For the reaction : \[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g)}\]
Equilibrium constant `K_C = ([NH3]^2)/([N_2][H_2]^3)`
Some reactions are written below in Column I and their equilibrium constants in terms of Kc are written in Column II. Match the following reactions with the corresponding equilibrium constant
| Column I (Reaction) | Column II (Equilibrium constant) |
| (i) \[\ce{2N2 (g) + 6H2 (g) ⇌ 4NH3 (g)}\] | (a) `2K_c` |
| (ii) \[\ce{2NH3 (g) ⇌ N2 (g) + 3H2 (g)}\] | (b) `K_c^(1/2)` |
| (iii) \[\ce{1/2 N2 (g) + 3/2 H2 (g) ⇌ NH3 (g)}\] | (c) `1/K_c` |
| (d) `K_c^2` |
Match standard free energy of the reaction with the corresponding equilibrium constant.
| Column I | Column II |
| (i) ∆GΘ > 0 | (a) K > 1 |
| (ii) ∆GΘ > 0 | (b) K = 1 |
| (iii) ∆GΘ = 0 | (c) K = 0 |
| (d) K < 1 |
Match the following species with the corresponding conjugate acid:
| Species | Conjugate acid |
| (i) \[\ce{NH3}\] | (a) \[\ce{CO^{2-}3}\] |
| (ii) \[\ce{HCO^{-}3}\] | (b) \[\ce{NH^{+}4}\] |
| iii) \[\ce{H2O}\] | (c) \[\ce{H3O+}\] |
| (iv) \[\ce{HSO^{-}4}\] | (d) \[\ce{H2SO4}\] |
| (e) \[\ce{H2CO3}\] |
Match the following graphical variation with their description
| A | B |
(i)  |
(a) Variation in product concentration with time |
(ii)  |
(b) Reaction at equilibrium |
(iii)  |
(c) Variation in reactant concentration with time |
Match Column (I) with Column (II).
| Column I | Column II |
| (i) Equilibrium | (a) ∆G > 0, K < 1 |
| (ii) Spontaneous reaction | (b) ∆G = 0 |
| (iii) Non spontaneous reaction | (c) ∆GΘ = 0 |
| (d) ∆G < 0, K > 1 |
Assertion (A): Increasing order of acidity of hydrogen halides is \[\ce{HF < HCl < HBr < HI}\]
Reason (R): While comparing acids formed by the elements belonging to the same group of periodic table, \[\ce{H - A}\] bond strength is a more important factor in determining acidity of an acid than the polar nature of the bond.
Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true but R is false.
Both A and R are false.
Assertion (A): A solution containing a mixture of acetic acid and sodium acetate maintains a constant value of \[\ce{pH}\] on addition of small amounts of acid or alkali.
Reason (R): A solution containing a mixture of acetic acid and sodium acetate acts as a buffer solution around \[\ce{pH}\] 4.75.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true but R is false.
Both A and R are false.
Assertion (A): The ionisation of hydrogen sulphide in water is low in the presence of hydrochloric acid.
Reason (R): Hydrogen sulphide is a weak acid.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is true but R is false.
Both A and R are false.
Assertion (A): For any chemical reaction at a particular temperature, the equilibrium constant is fixed and is a characteristic property.
Reason (R): Equilibrium constant is independent of temperature.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is true but R is false.
Both A and R are false.
Assertion (A): Aqueous solution of ammonium carbonate is basic.
Reason (R): Acidic/basic nature of a salt solution of a salt of weak acid and weak base depends on Ka and Kb value of the acid and the base forming it.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is true but R is false.
Both A and R are false.
Assertion (A): An aqueous solution of ammonium acetate can act as a buffer.
Reason (R): Acetic acid is a weak acid and \[\ce{NH4OH}\] is a weak base.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is false but R is true.
Both A and R are false.
Assertion (A): In the dissociation of \[\ce{PCl5}\] at constant pressure and temperature addition of helium at equilibrium increases the dissociation of \[\ce{PCl5}\].
Reason (R): Helium removes \[\ce{Cl2}\] from the field of action.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is true but R is false.
Both A and R are false.
How can you predict the following stages of a reaction by comparing the value of Kc and Qc?
(i) Net reaction proceeds in the forward direction.
(ii) Net reaction proceeds in the backward direction.
(iii) No net reaction occurs.
On the basis of Le Chatelier principle explain how temperature and pressure can be adjusted to increase the yield of ammonia in the following reaction.
\[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ∆H = - 92.38 kJ mol^{-1}}\]
What will be the effect of addition of argon to the above reaction mixture at constant volume?
A sparingly soluble salt having general formula \[\ce{A^{p+}_x B^{q-}_y}\] and molar solubility S is in equilibrium with its saturated solution. Derive a relationship between the solubility and solubility product for such salt.
Write a relation between ∆G and Q and define the meaning term and answer the following:
Why a reaction proceeds forward when Q < K and no net reaction occurs when Q = K.
Write a relation between ∆G and Q and define the meaning term and answer the following:
Explain the effect of increase in pressure in terms of reaction quotient Q. for the reaction: \[\ce{CO (g) + 3H2 (g) ⇌ CH4 (g) + H2O (g)}\]
Solutions for 7: Equilibrium
NCERT Exemplar solutions for Chemistry [English] Class 11 chapter 7 - Equilibrium
Shaalaa.com has the CBSE Mathematics Chemistry [English] Class 11 CBSE solutions in a manner that help students grasp basic concepts better and faster. The detailed, step-by-step solutions will help you understand the concepts better and clarify any confusion. NCERT Exemplar solutions for Mathematics Chemistry [English] Class 11 CBSE 7 (Equilibrium) include all questions with answers and detailed explanations. This will clear students' doubts about questions and improve their application skills while preparing for board exams.
Further, we at Shaalaa.com provide such solutions so students can prepare for written exams. NCERT Exemplar textbook solutions can be a core help for self-study and provide excellent self-help guidance for students.
Concepts covered in Chemistry [English] Class 11 chapter 7 Equilibrium are Concept of Equilibrium, Solid-liquid Equilibrium, Liquid-vapour Equilibrium, Solid - Vapour Equilibrium, Equilibrium Involving Dissolution of Solid in Liquids, Equilibrium Involving Dissolution of Gases in Liquids, General Characteristics of Equilibria Involving Physical Processes, Equilibrium in Chemical Processes - Dynamic Equilibrium, Law of Chemical Equilibrium and Equilibrium Constant, Equilibrium Constant in Gaseous Systems, Heterogeneous Equlibria, Predicting the Extent of a Reaction, Predicting the Direction of the Reaction, Calculating Equilibrium Concentrations, Relationship Between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G, Change of Concentration, Change of Pressure, Addition of Inert Gas, Change of Temperature, Effect of Catalyst, Ionic Equilibrium in Solution, Arrhenius, Bronsted-lowry and Lewis Concept of Acids and Bases, Concept of Ionization of Acids and Bases, The Ionization Constant of Water and Its Ionic Product, The pH Scale, Ionization Constants of Weak Acids, Ionization of Weak Bases, Relation Between Ka and Kb, Di- and Polybasic Acids and Di- and Polyacidic Bases, Factors Affecting Acid Strength, Common Ion Effect in the Ionization of Acids and Bases, Hydrolysis of Salts and the Ph of Their Solutions, Buffer Solutions, Concept of Solubility Equilibria of Sparingly Soluble Salts, Concept of Acid, Base, and Salt.
Using NCERT Exemplar Chemistry [English] Class 11 solutions Equilibrium exercise by students is an easy way to prepare for the exams, as they involve solutions arranged chapter-wise and also page-wise. The questions involved in NCERT Exemplar Solutions are essential questions that can be asked in the final exam. Maximum CBSE Chemistry [English] Class 11 students prefer NCERT Exemplar Textbook Solutions to score more in exams.
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