Free NCERT Solutions For Class 11 Chemistry Chapter 7 : Equilibrium Free PDF Download

Question 1:
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
(a) What is the initial effect of the change on vapour pressure?
(b) How do rates of evaporation and condensation change initially?
(c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Question 2:
What is Kc for the following equilibrium when the equilibrium concentration of each substance
is: [SO2]= 0.60 M, [O2] = 0.82 M and [SO3] = 1.90 M ?

Question 3:
At a certain temperature and total pressure of 105 Pa, iodine vapour contains 40% by volume
of I atoms.

Question 4:
Write the expression for the equilibrium constant, Kc for each of the following reactions:

Question 5:
Find out the value of Kc for each of the following equilibria from the value of Kp:

Question 7:
Explain why pure liquids and solids can be ignored while writing the equilibrium constant
expression?

Question 9:
Nitric oxide reacts with Br2 and gives nitrosyl bromide as per reaction given below:

Question 10:
At 450 K,10 =2.0* 10^10 Kp /bar for the given reaction at equilibrium.

Question 11:
A sample of HI(g) is placed in flask at a pressure of 0.2 atm. At equilibrium the partial pressure of HI(g) is 0.04 atm. What is Kpfor the given equilibrium?

Question 15:
At 700 K, equilibrium constant for the reaction

Question 16:
What is the equilibrium concentration of each of the substances in the equilibrium when the initial concentration of ICl was 0.78 M?

Question 17:
Kp = 0.04 atm at 899 K for the equilibrium shown below. What is the equilibrium concentration of C2H6 when it is placed in a flask at 4.0 atm pressure and allowed to come to equilibrium?

Question 18:
Ethyl acetate is formed by the reaction between ethanol and acetic acid and the equilibrium is
represented as:

Question 19:
A sample of pure PCl5 was introduced into an evacuated vessel at 473 K. After equilibrium was attained, concentration of PCl5 was found to be 0.5 ,10–1 mol L–1. If value of Kc is 8.3*10–3 , what are the concentrations of PCl3 and Cl2 at equilibrium?

Question 20:
One of the reactions that takes place in producing steel from iron ore is the reduction of iron (II) oxide by carbon monoxide to give iron metal and CO2

Question 22:
Bromine monochloride, BrCl decomposes into bromine and chlorine and reaches the equilibrium:

Question 23:
At 1127 K and 1 atm pressure, a gaseous mixture of CO and CO2 in equilibrium with solid
carbon has 90.55% CO by mass

Question 25:
Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

Question 26:
Which of the following reactions will get affected by increasing the pressure?Also, mention whether change will cause the reaction to go into forward or backward direction

Question 27:
The equilibrium constant for the following reaction is 1.6*105 at 1024 K

Question 28:
Dihydrogen gas is obtained from natural gas by partial oxidation with steam as per following
endothermic reaction:

Question 29:
Describe the effect of: (a) Addition of H2
b) Addition of CH3OH
c) Removal of CO
d) Removal of CH3OH on the equilibrium of the reaction:

Question 30:
At 473 K, equilibrium constant Krfor decomposition of phosphorus pentachloride, PCl5 is 8.3*10-3. If decomposition is depicted as,

Question 31:
Dihydrogen gas used in Haber’s process is produced by reacting methane from natural gas with high temperature steam. The first stage of two stage reaction involves the formation of CO and H2. In second stage, CO formed in first stage is reacted with more steam in water gas shift reaction

Question 32:
Predict which of the following reaction will have appreciable concentration of reactants and
products:

Question 35:
What is meant by the conjugate acid-base pair? Find the conjugate acid/base for the following
species:

Question 36:
Which of the followings are Lewis acids? H2O, BF3, H+, and NH4+

Solution 36:
Lewis acids are those acids which can accept a pair of electrons. For example, BF3, H+, and Page 24 NH4+are Lewis acids.

Question 37:
What will be the conjugate bases for the Brönsted acids: HF, H2SO4 and HCO3?

Question 38:
Write the conjugate acids for the following Brönsted bases: NH2–, NH3 and HCOO–.

Question 39:
The species: H2O, HCO3- HSO4- and NH3 can act both as Brönsted acids and bases. For each case give the corresponding conjugate acid and base.

Question 40:
Classify the following species into Lewis acids and Lewis bases and show how these act as
Lewis acid/base:
(a) OH–
(b) F-
(c) H+ (d)BCl3.

Question 41:
The concentration of hydrogen ion in a sample of soft drink is 3.8 *10^3 M. what is its pH?

Question 42:
The pH of a sample of vinegar is 3.76. Calculate the concentration of hydrogen ion in it.

Question 43: The ionization constant of HF, HCOOH and HCN at 298K are 6.8 10^4, 1.8 10^4 and 4.8 10^9 respectively. Calculate the ionization constants of the corresponding conjugate base.

Question 44:
The ionization constant of phenol is 1.0*10^10. What is the concentration of phenolate ion in 0.05 M solution of phenol? What will be its degree of ionization if the solution is also 0.01M in sodium phenolate?

Question 46:
The ionization constant of acetic acid is 1.74 *10^5. Calculate the degree of dissociationof acetic acid in its 0.05 M solution. Calculate the concentration of acetate ion in the solution and its pH.

Question 47:
It has been found that the pH of a 0.01M solution of an organic acid is 4.15. Calculate the concentration of the anion, the ionization constant of the acid and its pKa.

Question 48:
Assuming complete dissociation, calculate the pH of the following solutions:
(i) 0.003 M HCl
(ii) 0.005 M NaOH
(iii)0.002 M HBr
(iv)0.002 M KOH

Question 49:
Calculate the pH of the following solutions:
a) 2 g of TlOH dissolved in water to give 2 litre of solution.
b) 0.3 g of Ca(OH)2 dissolved in water to give 500 mL of solution.
c) 0.3 g of NaOH dissolved in water to give 200 mL of solution.
d) 1mL of 13.6 M HCl is diluted with water to give 1 litre of solution.

Question 50:
The degree of ionization of a 0.1M bromoacetic acid solution is 0.132. Calculate the pH of the solution and the pKa of bromoacetic acid.

Question 51:
The degree of ionization of a 0.1M bromoacetic acid solution is 0.132. Calculate the pH of the solution and the pKa of bromoacetic acid.

Question 52:
What is the pH of 0.001 M aniline solution? The ionization constant of aniline can be take from Table 7.7. Calculate the degree of ionization of aniline in the solution. Also calculate the ionization constant of the conjugate acid of aniline.

Question 53:
Calculate the degree of ionization of 0.05M acetic acid if its pKa value is 4.74. How is the degree of dissociation affected when its solution also contains (a) 0.01 M (b) 0.1 M in HCl?

Question 54:
The ionization constant of dimethylamine is 5.4*10^4. Calculate its degree of ionization in its 0.02 M solution. What percentage of dimethylamine is ionized if the solution is also 0.1 M in NaOH?

Question 55:
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
(a) Human muscle-fluid, 6.83
(b) Human stomach fluid, 1.2
(c) Human blood, 7.38
(d) Human saliva, 6.4.

Question 56:
The pH of milk, black coffee, tomato juice, lemon juice and egg white are 6.8, 5.0, 4.2,2.2 and
7.8 respectively. Calculate corresponding hydrogen ion concentration in each.

Question 57:
If 0.561 g of KOH is dissolved in water to give 200 mL of solution at 298 K. Calculate the concentrations of potassium, hydrogen and hydroxyl ions. What is its pH?

Question 58:
The solubility of Sr(OH)2 at 298 K is 19.23 g/L of solution. Calculate the concentrations of
strontium and hydroxyl ions and the pH of the solution.

Question 59:
The ionization constant of propanoic acid is 1.32 10^5. Calculate the degree of ionization of the acid in its 0.05M solution and also its pH. What will be its degree of ionization if the solution is 0.01M in HCl also?

Question 60:
The pH of 0.1M solution of cyanic acid (HCNO) is 2.34. Calculate the ionization constant of the acid and its degree of ionization in the solution.

Question 61:
The ionization constant of nitrous acid is 4.5*10^4. Calculate the pH of 0.04 M sodium nitrite solution and also its degree of hydrolysis.

Question 62:
A 0.02 M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization
constant of pyridine.

Question 63:
Predict if the solutions of the following salts are neutral, acidic or basic:
NaCl, KBr, NaCN, NH4NO3, NaNO2 and KF

Question 64:
The ionization constant of chloroacetic acid is 1.35*10^3. What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Question 65:
Ionic product of water at 310 K is 2.7*10^14. What is the pH of neutral water at this temperature?

Question 66:
Calculate the pH of the resultant mixtures:
a) 10 mL of 0.2M Ca(OH)2 + 25 mL of 0.1M HCl
b) 10 mL of 0.01M H2SO4 + 10 mL of 0.01M Ca(OH)2
c) 10 mL of 0.1M H2SO4 + 10 mL of 0.1M KOH

Question 67:
Determine the solubilities of silver chromate, barium chromate, ferric hydroxide, lead chloride and mercurous iodide at 298K from their solubility product constants given in Table 7.9 (page 221). Determine also the molarities of individual ions.

Question 68:
The solubility product constant of Ag2CrO4 and AgBr are 1.1*10–12 and 5.0*10^13respectively. Calculate the ratio of the molarities of their saturated solutions.

Question 69:
Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together.
Will it lead to precipitation of copper iodate?

Question 70:
The ionization constant of benzoic acid is 6.46*10^5 and Ksp for silver benzoate is 2.5*10^13 How many times is silver benzoate more soluble in a buffer of pH 3.19 compared to its solubility in pure water?

Question 71:
What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide so that when mixed in equal volumes, there is no precipitation of iron sulphide? (For iron sulphide, Ksp= 6.3*10–18).

Question 72:
What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1*10^6).

Question 73:
The concentration of sulphide ion in 0.1M HCl solution saturated with hydrogen sulphide is 1.0*10^19 M. If 10 mL of this is added to 5 mL of 0.04 M solution of the following:
FeSO4, MnCl2, ZnCl2 and CdCl2. in which of these solutions precipitation will take place
Given for 6.3* 10^-18 , 2.5 *10^-13 , 1.6 *10^-24 , 8.0 10^K Fes sp MnS ZnS CdS=8.2*10^-27