Dpp chemical equilibrium_jh_sir-3619

PAGE NO. # 1
ETOOS ACADEMY Pvt. Ltd
F-106, Road No.2 Indraprastha Industrial Area, End of Evergreen Motor,
BSNL Lane, Jhalawar Road, Kota, Rajasthan (324005) Tel. : +91-744-242-5022, 92-14-233303
* Marked Questions are having more than one correct option.
DPP No. # 13
1. For the equilibrium in a clsoed vessel
PCl5(g) PCl3(g) + Cl2(g)
Kp is found to be double of Kc. This is attained when :
(A) T = 2 K (B) T = 12.18 K (C) T = 24.36 K (D) T = 27.3 K
2. For the equilibrium 2H2 2H2(g) + O2(g) equilibrium constant is K1.
For the equilibrium 2CO2 2CO(g) + O2(g), equilibrium constant is K2.
The equilibrium constant for CO2(g) + H2(g) CO(s) + H2O(g) is :
(A) K1K2 (B)
1
2
K
K (C)
1
2
K
K (D)
2
1
K
K
3. For the reactionA(g) + B (g) C (g) at equilibrium the partial pressure of the species are PA = 0.15 atm,
PC = PB = 0.30 atm. If the capacity of reaction vessel is reduced, the equilibrium is reestablished. In the new
situation partial pressure A and B become twice. What is the partial pressure of C?
(A) 0.30 (B) 0.60 (C) 1.20 (D) 1.80
4. At temperature, T, a compound AB2(g) dissociates according to the reaction 2AB2(g) 2AB (g) + B2(g)
with a degree of dissociation, x, which is small compared with unity. Deduce the expression for Kp, in terms
of x and the total pressure, P.
(A)
3
Px
2
(B)
2
Px
3
(C)
3
Px
3
(D)
2
Px
2
5. For the reaction
N2O4 2NO2, at 350 K, the value of Kc = 0.4. The value of Kp for the reaction at the same temperature
would be :
(A) 11.49 atm (B) 1.148 atm (C) 1.4 × 10–2 atm (D) 1.4 × 10–3 atm
6. Two moles of HI were heated in a sealed tube at 440ºC till the equilibrium was reached. HI was found to be
22% decomposed. The equilibrium constant for dissociation is :
(A) 0.282 (B) 0.0796 (C) 0.0199 (D) 1.99
CHEMISTRY
DAILY PRACTICE PROBLEMS
D P P
COURSE NAME : URJAA (UR) DATE : 29.07.2013 to 03.08.2013 DPP NO. 13 & 14
TARGET
JEE (ADVANCED) : 2014

PAGE NO. # 2
7. For A 2B equilibrium constant at total pressure p1 is kp1
& for C D + E equilibrium constant at total
pressure p2 is kp2
. If both reaction are gaseous homogeneous reaction and degree of dissociation of A and
C are same, then the ratio of p1/p2 if kp1
= 2 kp2
is :
(A) 1/2 (B) 1/3 (C) 1/4 (D) 2
8.
1
2
N2(g) + O2(g) NO2(g) ... K1
2NO2(g) N2O4 (g) ... K2
Given that above reaction have equilibrium constants K1 and K2 respectively. What would be the expres-
sion for the equilibrium constant K for the following reaction, in terms of K1 and K2?
N2O4 (g) N2(g) + 2O2(g)
(A) K1K2 (B) 2
1 2
1
K (K ) (C) 2
2 1
1
K (K ) (D)
1 2
1
K K
9. At a certain temperature the equilibrium constant (Kc) is 16 for the reaction
SO2 (g) + NO2 (g) SO3 (g) + NO (g)
It we take one mole of each of the four gases in a one-litre container, what would be the equilibrium
concentration of NO and NO2?
10. For an equilibrium A + 2B 2 C + D ; A and B are mixed in a reaction vesel at 300 K. The initial
concentration of B was 1.5 times the intial concentration of A. After the equilibrium, the equilibrium
concentration of A and D are same. Calculate KC.
DPP No. # 14
1. n mole of PCl3 and n mole of Cl2 are allowed to react at constant temperature T under a total pressure P, as
PCl3 (g) + Cl2 (g) PCl5(g)
If Y mole of PCl5 are formed at equilibrium, find KP
2. The reaction, SO2 + Cl2 SO2Cl2 is exothermic and reversible. A mixture of SO2 (g), Cl2(g) and
SO2Cl2() is at equilibrium in a closed container. Now a certain quantity of extra SO2 is introduced into the
container, the volume remaining the same. Which of the following are true?
(A) The pressure inside the container will not change
(B) The temperature will not change
(C) The temperature will increase (D) The temperature will decrease
3. What are the most favourable conditions for the reaction ;
SO2(g) +
1
2
O2(g) SO3(g) ; H = – ve to occur?
(A) low temperature, high pressure (B) low temperature, low pressure
(C) high temperature, low pressure (D) high temperature, high pressure
4. For the reaction 2NO2(g) 2NO(g) + O2(g)
Kc = 1.8 × 10–6 at 184ºC
Given : R = 0.083 kJ K–1 mol–1
when Kp and Kc are compared at 184ºC it is found that :
(A) Kp is greater than Kc (B) Kp is less than Kc
(C) Kp = Kc
(D) whether Kp is greater than, less than or equal to Kc depends upon the total gas pressure

PAGE NO. # 3
5. The unit of equilibrium constant KC of a reaction is mol–2 2. For this reaction, the product concentration
increases by :
(A) increasing the pressure (B) lowering the temperature
(C) lowering the pressure (D) both B and C
6. The equilibrium constant for the reaction
A2(g) + B2(g) 2AB(g) is 20 at 500 K.
The equilibrium constant for the reaction,
2AB(g) AA2(g) + B2(g), would be :
(A) 20 (B) 0.5 (C) 0.05 (D) 10
7. The equilibrium N2 + O2 estabilished in a reaction vessel of 2.5 L capacity. The amounts of N2 and O2 taken
at the start were respectively 2 moles and 4 moles. Half a mole of nitrogen has been used up at equilibrium.
The molar concentration of nitric oxide is :
(A) 0.2 (B) 0.4 (C) 0.6 (D) 0.1
8. In an evacuated closed isolated chamber at 250ºC 0.02 mole PCl5 and 0.01 mole Cl2 are mixed
(PCl5 PCl3 + Cl2). At equilibrium density of mixture was 2.48 g/L and pressure was 1 atm. The
number of total moles at equilibrium will be approximately :
(A) 0.012 (B) 0.022 (C) 0.032 (D) 0.045
9. In the following reaction, 3A + B 2C + D
Intial mol of B is double of A. At equilibrium mole of A and C are equal. Hence % dissociation of B is :
3A + B 2C + D
(A) 10% (B) 20% (C) 40% (D) 5%
10. 200 gm of CaCO3 (s) taken in 4 Litre container at a certain temperature. Kc for the dissociation of CaCO3
at this temperature is found to be 1/4 mole litre–1, then the concentration of CaO in mole/litre is :
[Given : CaO = 1.12 gm cm–3] [Ca = 40, O = 16]
(A) 1/2 (B) 1/4 (C) 0.02 (D) 20
ANSWER KEY
DPP No. # 13
1. (C) 2. (D) 3. (C) 4. (A) 5. (A) 6. (C) 7. (A)
8. (C)
9. [NO] = 1 + x = 1 + 0.6 = 1.6 moles/litres
[NO2] = 1 – x = 1 – 0.6 = 0.4 moles/litre.
10. 4
DPP No. # 14
1. Kp =
5
3 2
PCl
2
PCl Cl
yP
P (2n y)y2n y
(P )(P ) (n y) Pn y n y
P P
2n y 2n y

 
    
    
    
2. (C) 3. (A) 4. (A)
5. (A) 6. (C) 7. (B) 8. (D) 9. (A) 10. (D)

PAGE NO. # 1
* Marked Questions are having more than one correct option.
DPP No. # 15
1. At a certain temperature, the equilibrium constant (Kc) is 16 for the reaction
SO2(g) + NO2(g) SO3 (g) + NO (g)
It we take one mole of each of the four gases in a one-litre container, what would be the equilibrium
concentration of NO and NO2?
2. For NH4HS (s) NH3(g) + H2S (g), for a reaction started with NH4HS(s), the observed pressure for
reaction mixture in equilibrium is 1.12 atm at 106ºC. What is the value of Kp for the reaction?
3. The equilibrium constant for the following reaction, H2(g) + Br2(g) 2 HBr (g) is 1.6 × 105 at 1024 K.
Find the equilibrium pressure of all gases if 10 bar of HBr is introduced into a sealed container at 1024 K.
4. The degree of dissociation of PCl5() obeying the equilibrium,
PCl5 PCl3 + Cl2, is approximately related to the pressure at equilibrium by :
(A)  P (B) 
1
P
(C)  2
1
P
(D)  4
1
P
5. Two moles of HI were heated in a sealed tube at 440ºC till the equilibrium was reached. HI was found to be
22% decomposed. The equilibrium constant for dissociation is :
2HI H2 + I2
(A) 0.282 (B) 0.0796 (C) 0.0199 (D) 1.99
6. For the following equilibrium N2O4 2NO2 in gaseous phase, NO2 is 50% of the total volume when
equilibrium is set up. Hence percent of dissociation of N2O4 is :
(A) 50% (B) 25% (C) 66.66% (D) 33.33%
7. A 10 L container at 300 K contains CO2 gas at pressure of 0.2 atm and an excess solid CaO (neglect the
volume of solid CaO). The volume of container is now decreased by moving the movable piston fitted in the
container. What will be the maximum volume of container when pressure of CO2 attains its maximum value
given that
CaCO3 (s) CaO(s) + CO2(g) Kp = 0.800 atm
(A) 5 L (B) 2.5 L
(C) 1 L (D) The information is insufficient
8. A container contains three gases. A, B and C in equilibrium A 2B + C
At equilibrium the concentration of A was 3M, and of B was 4 M. On doubling the volume of container, the
new equilibrium concentration of B was 3M. Calculate KC and initial equilibrium concentration of C.
9. The vapour density of N2O4 at a certain temperature is 30. What is the percentage dissociation of N2O4 at
this temperature?
(A) 53.3% (B) 106.6% (C) 26.7% (D) none
10. A sample of mixture of A (g), B (g) and C (g) under equilibrium has a mean molecular weight (observed) is
80. The equilibrium is
A (g) B(g) + C(g)
(mol. wt. = 100) (mol. wt. = 60) (mol. wt. = 40)
Find the degree of dissociation  for A (g)
(A) 0.25 (B) 0.5 (C) 0.75 (D) 0.8
CHEMISTRY
DAILY PRACTICE PROBLEMS
D P P
COURSE NAME : URJAA (UR) DATE : 05.08.2013 to 10.08.2013 DPP NO. 15 & 16
TARGET
JEE (ADVANCED) : 2014

PAGE NO. # 2
DPP No. # 16
1. The correct relationship between free energy change in a reaction and the corresponding equilibrium
constant K is : [RPMT 2008]
(A) – Gº = RT ln K (B) G = RT ln K (C) – G = RT ln K (D) Gº = RT ln K
2. Which of the following is not favourable for SO3 formation
2SO2(g) + O2(g) 2SO3(g) ; H = – 45.0 kcal
(A) High pressure (B) High temperature
(C) Decreasing SO3 concentration (D) Increasing reactant concentration
3. In an equilibrium reaction for which Gº = 0, the value of equilibrium constant K =
(A) 0 (B) 1 (C) 2 (D) 10
4. In which of the following equilibrium reactions, the equilibrium would shift to right side, if total pressure is
decreased :
(A) N2 + 3H2 2NH3 (B) H2 + I2 2HI
(C) N2O4 2NO2 (D) H2 + Cl2 2HCl
5. On cooling of following system at equilibrium CO2(s) CO2(g)
(A) There is no effect on the equilibrium state (B) More gas is formed
(C) More gas solidfies (D) None of above
6. For an equilibrium H2O (s) H2O () which of the following statement is true :
(A) The pressure changes do not affect the equilibrium
(B) More of ice melts if pressure on the system is increased
(C) More of liquid freezes if pressure on the system is increased
(D) The pressure changes may increase or decrease the degree of advancement of the reaction depending
upon the temperature of the system.
7. CaCO3 is heated in a closed vessel to establish the equilibrium CaCO3 CaO + CO2. The amount of
CaO present in the vessel at equilibrium will increase if :
(A) some CaCO3 is added to the vessel (B) some CaO is added to the vessel
(C) some BaO is added to the vessel (D) some CO2 is added to the vessel
8. The chemical reaction : BaO2(s) BaO(s) + O2(g)
H = + ve. In equilibrium condition, pressure of O2 depends upon :
(A) increase mass of BaO (B) increase mass of BaO2
(C) increase in temperature (D) increase mass of BaO2 and BaO both
9. The following equilibrium constant are given
N2 + 3H2 2NH3 ; K1
N2 + O2 2NO ; K2
H2 + 2
1
O
2
H2O ; K3
The equilibrium constant for the oxidation of NH3 by oxygen to give NO is :
(A) K1K2/K3 (B) K2K3
3/K1 (C) K2K2
3/K1 (D) K2
2K3/K1
10. Consider the following equilibrium in a closed container :
N2O4 (g) 2NH3(g)
At a fixed temperature, the volume of the reaction container is halved. For this change, which of the
following statements, holds true regarding the equilibrium constant (Kp) and degree of dissociation ()
(A) neither Kp nor  changes (B) both Kp and  change
(C) Kp changes but  does not change (D) Kp does not change but  changes
ANSWER KEY
DPP No. # 15
1. [NO] = 1 + x = 1 + 0.6 = 1.6 moles/litre ; [NO2] = 1 – x = 1 – 6 = 0.4 moles/litre.
2. 0.3136 atm2 3. HBrP 10 p ~10bar~  4. (B) 5. (C) 6. (D)
7. (B) 8. 28.8 9. (A) 10. (A)
DPP No. # 16
1. (A) 2. (B) 3. (B) 4. (C) 5. (C) 6. (B) 7. (A)
8. (C) 9. (B) 10. (D)

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