Back to ExamsBack
0 of 126 answered
Chemistry
Chemical Equilibrium
126 questions · Click an option and press Check Answer to reveal the result
1
Kₚ/Kc for the gaseous reaction –
(a) 2 A + 3 B ⇌ 2C
(b) 2 A ⇌ 4B
(c) A + B + 2C ⇌ 4D would be respectively -
A
(RT)⁻³ , (RT)² , (RT)⁰
B
(RT)⁻³ , (RT)⁻² , (RT)⁻¹
C
(RT)⁻³ , (RT)² , (RT)
D
None of the above
2
The role of catalyst in reversible reaction is-
A
To increase the rate of forward reaction
B
Decrease the rate after equilibrium
C
Allow equilibrium to be achieved quickly
D
None
3
Percentage yield of following reaction is plotted against pressure at a definite temperature : 2SO₂(g) + O₂(g) ⇌ 2SO₃(g); ΔH = −ve Which of the following relation is correct ?
A
T₁ > T₂ > T₃
B
T₃ > T₂ > T₁
C
T₁ = T₂ = T₃
D
T₁ > T₂ < T₃
4
At any moment before a reversible reaction attains equilibrium it is found that –
A
The rate of the forward reaction is increasing and that of backward reaction is decreasing
B
The rate of the forward reaction is decreasing and that of backward reaction is increasing
C
The rate of both forward and backward reactions is increasing
D
The rate of both forward and backward reactions is decreasing
5
According to Le Chatelier principle, an increase in the temperature of the following reaction will N₂ + O₂ ⇌ 2NO − 43200 cal
A
Increase the yield of NO
B
Decrease the yield of NO
C
Not effect on the yield of NO
D
Not help the reaction to proceed
6
The relation between Kp and Kc for the reaction A + B ⇌ C + 2D is –
A
Kp = Kc(RT)⁻¹
B
KpKc⁻¹ = RT
C
KcKp⁻¹ = RT
D
Kp = Kc(RT)³
7
The reaction A + B ⇌ C + D is studied in a one litre vessel at 250°C. The initial concentration of A was 3n and the initial concentration of B was n. After equilibrium was attained then equilibrium concentration of C was found to be equal to equilibrium concentration of B. What is the concentration of D at equilibrium ?
A
n/2
B
(3n − n/2)
C
n
D
None of these
8
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. The expression for Kp, in terms of x and the total pressure, P is
A
.
B
.
C
.
D
.
9
If the pressure in a reaction vessel for the following reaction is increased by decreasing the volume, what will happen to the concentrations of CO and CO₂ ? H₂O(g) + CO(g) ⇌ H₂(g) + CO₂(g) + Heat
A
both the [CO] and [CO₂] will decrease
B
neither the [CO] nor the [CO₂] will change
C
both [CO] will decrease and the [CO₂] will increase
D
both the [CO] and [CO₂] will increase
10
In an equilibrium reaction for which ΔG° = 0, the equilibrium constant K should be equal to –
A
0
B
1
C
2
D
10
11
For dissociation of PCl₅,mole fraction of Cl₂ at equilibrium is 0.3. The total pressure is 1.0 atmosphere. The partial pressure of PCl₃ at equilibrium is –
A
1.3
B
0.3
C
0.7
D
0.4
12
Which of the following reaction will be favoured at low pressure -
A
H₂(g) + I₂(g) ⇌ 2HI(g)
B
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
C
PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)
D
N₂(g) + O₂(g) ⇌ 2NO(g)
13
The statement not applicable to an irreversible reaction is –
A
It goes to completion in the forward direction
B
On increasing the concentration of the reactants, the rate of the reaction increases
C
The removal of the reaction products makes the reaction faster
D
The addition of the reaction products does not influence the rate of reaction
14
For the reaction N2 + 3H2 →2NH3 , N2 & H2 were taken in the molar ratio of 1 : 3 . Up to the point of equilibrium 50% each reactant has been reacted. If total pressure at equilibrium is P. The partial pressure of ammonia would be
A
P/3
B
P/6
C
P/4
D
P/8
15
Consider the reaction, (i) PCl₅(g) ⇌ PCl₃(g) + Cl₂(g) (ii) N₂O₄(g) ⇌ 2NO₂(g) The addition of an inert gas at constant volume -
A
will increase the dissociation of PCl₅ as well as N₂O₄
B
will reduce the dissociation of PCl₅ as well as N₂O₄
C
will increase the dissociation of PCl₅ and step up the formation of NO₂
D
will not disturb the equilibrium of the reactions
16
In which of the following reaction, the value of Kₚ will be equal to Kc –
A
N₂(g) + O₂(g) ⇌ 2NO(g)
B
PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)
C
2NH₃(g) ⇌ N₂(g) + 3H₂(g)
D
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
17
The value of Kp for the reaction 2H₂S(g) ⇌ 2H₂(g) + S₂(g) is 1.2 × 10⁻² at 1065°C. The value of Kc for this reaction is–
A
1.2 × 10⁻²
B
< 1.2 × 10⁻²
C
83
D
> 1.2 × 10⁻²
18
Which of the following will shift the reaction PCl₃(g) + Cl₂(g) ⇌ PCl₅(g) to the left side-
A
Addition of PCl₅
B
Increase in pressure
C
Decrease in temperature
D
Catalyst
19
An unknown compound A dissociates at 500°C to give products as follows - A(g) ⇌ B(g) + C(g) + D(g) Vapour density of the equilibrium mixture is 50 when it dissociates to the extent to 10%. What will be the molecular weight of Compound A –
A
120
B
130
C
134
D
140
20
Decomposition of N₂O₄(g) takes place as follows : N₂O₄(g) ⇌ 2NO₂(g) 'D' is the vapour density at initial stage and 'd' is the vapour density at equilibrium. We get following graph when the degree of dissociation 'a' is plotted against (D/d) What is the value of D/d at A ?
A
0
B
0.5
C
1
D
1.5
21
In the reaction C₂H₄(g) + H₂(g) ⇌ C₂H₆(g), the equilibrium constant can be expressed in units of -
A
litre⁻¹ mol⁻¹
B
mol² litre⁻²
C
litre mol⁻¹
D
mol litre⁻¹
22
At a total pressure of 2 atmospheres, the number of moles of N₂, H₂ and NH₃ at equilibrium in a gaseous mixture are 1, 3 and 2. The partial pressure of NH₃ in atmospheres is –
A
1.0
B
0.5
C
0.33
D
0.67
23
At 35°C, the equilibrium constant for the reaction below is 2NOCl(g) ⇌ 2NO(g) + Cl₂(g) Kc = 1.6 × 10⁻⁵ An equilibrium mixture was found to have the following concentration of Cl₂ and NOCl. [Cl₂] = 1.2 × 10⁻² M [NOCl] = 2.8 × 10⁻¹ M Calculate the concentration of NO(g) at equilibrium :
A
1.0 × 10⁻⁴ M
B
1.0 × 10⁻² M
C
2.8 × 10⁻¹ M
D
2.4 × 10⁻² M
24
For the reaction A(g) + B(g) ⇌ C(g) + D(g), the degree of dissociation α would be –
A
√K/(√K + 1)
B
√K + 1
C
√K ± 1
D
√K − 1
25
N₂O₄ dissociates as N₂O₄(g) ⇌ 2NO₂(g) at 273 K and 2 atm pressure. The equilibrium mixture has a vapour density of 41. What will be the degree of dissociation -
A
14.2%
B
16.2%
C
12.2%
D
None
26
In a chemical equilibrium, the equilibrium constant is found to be 2.5. If the rate constant of backward reaction is 3.2 × 10⁻², the rate constant of forward reaction is -
A
8.0 × 10⁻²
B
4.0 × 10⁻²
C
3.5 × 10⁻²
D
7.6 × 10⁻³
27
If Kp for the reaction A(g) + 2B(g) ⇌ 3C(g) + D(g) is 0.05 atm. at 1000 K. Its Kc in terms of R will be –
A
20000 R
B
0.02 R
C
5 × 10⁻⁵ R
D
(5 × 10⁻⁵)/R
28
When H₂ is added to an equilibrium mixture 2HI(g) ⇌ H₂(g) + I₂(g), at constant temperature, the-
A
Value of Kₚ decreases
B
Value of Kₚ increases
C
The degree of dissociation of HI decreases
D
Degree of dissociation of HI increases
29
In the formation of nitric acid, N₂ and O₂ are made to combine. Thus N₂ + O₂ ⇌ 2NO − Heat Which of the following conditions will favour the formation of NO –
A
Low temperature
B
High temperature
C
High pressure
D
All are favourable
30
For the reaction PCl₅(g) ⇌ PCl₃(g) + Cl₂(g), the forward reaction at constant temperature is favoured by -
A
Increasing the volume of container
B
Introducing an inert gas at constant pressure
C
Introducing PCl₅ at constant volume
D
All of these
31
For the reaction, N₂O₄(g) ⇌ 2NO₂(g); if percentage dissociation of N₂O₄ are 25%, 50%, 75% and 100%, then the sequence of observed vapour densities will be -
A
d₁ > d₂ > d₃ > d₄
B
d₄ > d₃ > d₂ > d₁
C
d₁ = d₂ = d₃ = d₄
D
(d₁ = d₂) > (d₃ = d₄)
32
Given the following reaction at equilibrium, N₂(g) + 3H₂(g) ⇌ 2NH₃(g) Some inert gas at constant pressure is added to the system. Predict which of the following facts will be affected ?
A
More NH₃(g) is produced
B
Less NH₃(g) is produced
C
No affect on the equilibrium
D
Kp of the reaction is decreased
33
In the reaction N₂(g) + 3H₂(g) ⇌ 2NH₃(g), the forward reaction is exothermic and the backward reaction is endothermic. In order to produce more heat it is necessary –
A
To add ammonia
B
To add N₂ and H₂
C
Increasing the concentration of N₂, H₂ and NH₃ equally
D
None of the above
34
2SO₂ + O₂ ⇌ 2SO₃ + 47 Kcal. If large excess of oxygen is added to the above system in equilibrium this will -
A
Shift the equilibrium to the right
B
Shift the equilibrium to the left
C
Cause no change in the equilibrium
D
Produce only enormous amount of heat
35
Factors affecting Kc is/are -
A
Increasing concentration of the reactant
B
Presence of catalyst
C
Method of writing balanced equation (or stoichiometry of reaction)
D
Time taken by the chemical reaction
36
Select the correct expression regarding the relation between Kₚ and Kc for the reaction
aX(g) + bY(g) ⇌ bZ(g) + aW(g) -
A
Kₚ = Kc(RT)ᵃ⁺ᵇ
B
Kₚ = Kc/(a + b)²
C
Kₚ = KcRT
D
Kₚ = Kc
37
Which of the following statements is false in case of equilibrium state –
A
There is no apparent change in properties with time
B
It is dynamic in nature
C
It can be attained from either side of the reaction
D
It can be attained from the side of the reactants only
38
The equilibrium constants for the reaction X₂ ⇌ 2X at 300K and 600K are 10⁻⁸ and 10⁻³ respectively. The reaction is –
A
Exothermic
B
Endothermic
C
Thermo neutral
D
Slow
39
Which of the following conditions will be favourable for the formation of HX according to the gaseous equilibrium : H₂X₂ + heat ⇌ 2HX –
A
High temperature and high pressure
B
High temperature and low pressure
C
Low temperature and low pressure
D
High pressure and low temperature
40
The reaction in which the yield of the products cannot be increased by the application of high pressure is –
A
PCl₃(g) + Cl₂(g) ⇌ PCl₅(g)
B
N₂(g) + O₂(g) ⇌ 2NO(g)
C
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
D
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
41
The reaction A(g) + B(g) ⇌ C(g) + D(g) proceeds to right hand side upto 99.9%. The equilibrium constant K for the reaction will be -
A
10⁴
B
10⁵
C
10⁶
D
10⁸
42
The value of Kₚ for the reaction H₂(g) + I₂(g) ⇌ 2HI(g) is 50. What is the value of Kc
A
30
B
40
C
50
D
70
43
At constant pressure, the presence of inert gases -
A
reduces the dissociation of PCl₅
B
increases the dissociation of PCl₅
C
does not affect the degree of dissociation of PCl₅
D
steps up the formation of PCl₅
44
At 35°C, the equilibrium constant for the reaction below is 2NOCl(g) ⇌ 2NO(g) + Cl₂(g) Kc = 1.6 × 10⁻⁵ An equilibrium mixture was found to have the following concentration of Cl₂ and NOCl. [Cl₂] = 1.2 × 10⁻² M [NOCl] = 2.8 × 10⁻¹ M Calculate the concentration of NO(g) at equilibrium :
A
1.0 × 10⁻⁴ M
B
1.0 × 10⁻² M
C
2.8 × 10⁻¹ M
D
2.4 × 10⁻² M
45
For N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + Heat –
A
Kₚ = Kc
B
Kₚ = KcRT
C
Kₚ = Kc(RT)⁻²
D
Kₚ = Kc(RT)⁻¹
46
Determine the value of equilibrium constant (Kc) for the reaction A₂(g) + B₂(g) ⇌ 2AB(g) If 10 moles of A₂, 15 moles of B₂ and 5 moles of AB are placed in a 2 litre vessel and allowed to come to equilibrium. The final concentration of AB is 7.5 M :
A
4.5
B
1.5
C
0.6
D
None of these
47
The equilibrium constant of the reaction A + B ⇌ C + D is 10. If rate constant of forward reaction is 203, the rate constant of backward reaction is –
A
20.3
B
10.3
C
2.03
D
203
48
When 1 mole H₂O(g) and 1 mole CO(g) are heated at 1000°C in a closed vessel of 5 litre, it was found that 40% of H₂O react at equilibrium, according to H₂O(g) + CO(g) ⇌ H₂(g) + CO₂(g) Kc of the reaction will be -
A
0.444
B
0.555
C
0.666
D
0.786
49
For NH₄HS(s) ⇌ NH₃(g) + H₂S(g), if Kp = 64 atm², equilibrium pressure of mixture is :
A
8 atm
B
16 atm
C
64 atm
D
4 atm
50
At 444° C, the equilibrium constant K for the reaction 2AB(g) ⇌ A₂(g) + B₂(g) is 1/64. The degree of dissociation of AB will be -
A
10%
B
20%
C
30%
D
50%
51
In the system, LaCl3(s) + H2O(g) + heat ⇌ LaClO(s) + 2HCl(g), equilibrium is established. More water vapour is added to reestablish the equilibrium. The pressure of water vapour is doubled. The factor by which pressure of HCl is changed is:
A
2
B
√2
C
√3
D
√5
52
The equilibrium constant for the reaction N₂(g) + O₂(g) ⇌ 2NO(g) is 4 × 10⁻⁴ at 2000 K. In the presence of catalyst, the equilibrium is attained 10 times faster. The equilibrium constant in the presence of catalyst, at 2000 K is–
A
40 × 10⁻⁴
B
4 × 10⁻⁴
C
4 × 10⁻²
D
Difficult to compute without more data
53
At a total equilibrium pressure of 1.0 atmosphere, the degree of dissociation of phosgene is 0.2 COCl₂(g) ⇌ CO(g) + Cl₂(g) Now the same equilibrium is established at the same temperature in presence of N₂ gas at a partial pressure of 0.4 atm. in a total pressure of 1.0 atm. The new degree of dissociation, α, is –
A
α < 0.2
B
α > 0.2
C
α = 0.2
D
α = 0
54
In a 10 litre box 2.5 mole hydroiodic acid is taken. After equilibrium 2HI ⇌ H₂ + I₂ the concentration of HI is found to be 0.1 mol l⁻¹. The concentration of [H₂] at equilibrium in mol l⁻¹, is –
A
2.4
B
0.15
C
1.5
D
7.5 × 10⁻²
55
For an exothermic reaction in which the number of moles of reactants are more than the number of moles of products. In order to displace the reaction in the reverse direction, what are the favourable conditions .
A
High pressure, low temp. and high conc. of the product
B
Low pressure, high temp. and high conc. of the products
C
Low pressure, low temp. and high conc. of the products
D
High pressure, high temp. and low conc. of the products
56
For the reaction at equilibrium – CO₂(g) + H₂(g) ⇌ CO(g) + H₂O(g) [P – total pressure and x = degree of dissociation]
A
PCO₂ and PH₂ is equal to [(1−x)/2]P
B
PCO and PH₂ is equal to [(1−x)/2]P
C
PH₂ and PH₂O is equal to [x/2]P
D
PCO₂ and PH₂O is equal to [x/2]P
57
The oxidation of SO₂ to SO₃ by oxygen is an exothermic reaction. The yield of SO₃ will be maximum if –
A
Temperature is increased and pressure is kept constant
B
Temperature is reduced and pressure is increased
C
Both temperature and pressure are increased
D
Both temperature and pressure are decreased
58
In the reaction : NH₂COONH₄(s) ⇌ 2NH₃(g) + CO₂(g) the equilibrium pressure was 3 atm at 1000 K. The Kp of the reaction -
A
27
B
4
C
4/27
D
27/4
59
In the melting of ice, which one of the conditions will be more favourable –
A
High temperature and high pressure
B
Low temperature and low pressure
C
Low temperature and high pressure
D
High temperature and Low pressure
60
When a reversible reaction has reached the state of equilibrium -
A
The forward reaction stops
B
The backward reaction stops
C
The whole reaction stops
D
The forward and backward reaction proceed with same speed
61
A(l) + B(l) ⇌ C(l) + D(l) One mole of A and one mole of B are mixed in a volume of one litre. If 0.9 mole per litre of C is found at equilibrium, the equilibrium constant Kc is –
A
1
B
81
C
10
D
10⁻¹
62
In a dilute solution there are two equilibria KCl(s) ⇌ K⁺ + Cl⁻ ... K₁ = 10ˣ Ag⁺ + Cl⁻ ⇌ AgCl(s) ... K₂ = 10ʸ The equilibrium constant for the reaction Ag⁺ + KCl(s) ⇌ K⁺ + AgCl(s) in dilute solution is -
A
10ˣ⁺ʸ
B
10ˣ⁻ʸ
C
10ʸ
D
(10ˣ)ʸ
63
Consider the following reactions at equilibrium and determine which of the indicated changes will cause the reaction to proceed to the right - (1) CO(g) + 3H₂(g) ⇌ CH₄(g) + H₂O(g) (add CH₄) (2) N₂(g) + 3H₂(g) ⇌ 2NH₃(g) (remove NH₃) (3) H₂(g) + F₂(g) ⇌ 2HF(g) (add F₂) (4) BaO(s) + SO₃(g) ⇌ BaSO₄(s) (add BaO)
A
2, 3
B
1, 4
C
2, 4
D
2, 3, 4
64
For the reaction : PCl₃(g) + Cl₂(g) ⇌ PCl₅(g) at 250°C the Value of Kc is 26, then the value of Kp at the same temp. will be –
A
0.61
B
0.57
C
0.83
D
0.46
65
The Kc for the reaction A + B ⇌ C + D is 9. If one mole of each of A and B are initially mixed and there is no change in volume, the number of moles of C formed is –
A
0.50
B
0.75
C
0.90
D
1.5
66
For the reaction, 2NO₂(g) ⇌ 2NO(g) + O₂(g), Kc = 1.8 × 10⁻⁶ at 185°C. At 185°C, the value of Kc for the reaction - NO(g) + ½ O₂(g) ⇌ NO₂(g) is -
A
0.9 × 10⁶
B
7.5 × 10²
C
1.95 × 10⁻³
D
1.95 × 10³
67
The value of equilibrium constant for a reaction depends on-
A
Temperature
B
Pressure
C
Volume
D
Catalytic agent
68
K₁ and K₂ are the rate constants of forward and backward reactions. The equilibrium constant K of the reaction is -
A
K₁ × K₂
B
K₁ − K₂
C
K₁/K₂
D
(K₁ + K₂)/(K₁ − K₂)
69
In the following reactions –
(a) 2N₂O₅(g) ⇌ 4NO₂(g) + O₂(g)
(b) 4NO₂(g) + O₂(g) ⇌ 2N₂O₅(g)
Choose the correct fact –
A
(a) Kp > Kc ; (b) Kp = Kc
B
(a) Kp > Kc ; (b) Kp < Kc
C
(a) Kp = Kc ; (b) Kp < Kc
D
(a) Kp < Kc ; (b) Kp > Kc
70
At 500K, the equilibrium constant for the reaction cis-C₂H₂Cl₂ ⇌ trans-C₂H₂Cl₂ is 0.6. At the same temperature, the equilibrium constant for the reaction trans-C₂H₂Cl₂ ⇌ cis-C₂H₂Cl₂ will be –
A
0.66
B
1.67
C
0.76
D
2.6
71
The equilibrium constant Kc for the decomposition of PCl₅ is 0.625 mole / lit at 300°C. Then the value of Kₚ is -
A
29.402 atm
B
0.0625 atm
C
6.25 atm
D
0.00625 atm
72
For the reaction C(s) + CO₂(g) ⇌ 2CO(g) the partial pressure of CO₂ and CO are 2.0 and 4.0 atm respectively at equilibrium. The Kₚ for the reaction is –
A
0.5
B
4.0
C
8.0
D
32.0
73
For the reaction A(g) + 3B (g) →2C (g) at 27°C, 2 moles of A, 4 moles of B and 6 moles of C are present in 2 litre vessel. If KC for the reaction is 1.2, the reaction will proceed in :
A
forward direction
B
backward direction
C
neither direction
D
None of these
74
Some inert gas is added at constant volume to the following reaction at equilibrium NH₄HS(s) ⇌ NH₃(g) + H₂S(g) Predict the effect of adding the inert gas -
A
the equilibrium shifts in the forward direction
B
the equilibrium shifts in the backward direction
C
the equilibrium remains unaffected
D
the value of Kp is increased
75
In the equilibrium N₂ + 3H₂ ⇌ 2NH₃ + 22 Kcal the formation of ammonia is favoured by –
A
Increasing the pressure
B
Increasing the temperature
C
Decreasing the pressure
D
Adding ammonia
76
At a given temperature the following reaction is allowed to reach equilibrium in a vessel of volume V₁ litre. The degree of dissociation is α₁. If by keeping the temperature fixed the volume of the reaction vessel is doubled (assuming the degrees of dissociation to be small) the new degree of dissociation shall be – PCl₅ ⇌ PCl₃ + Cl₂
A
2α₁
B
√(α₁/2)
C
√(2α₁)
D
√2 α₁
77
Adding inert gas to system N₂(g) + 3H₂(g) ⇌ 2NH₃(g) at equilibrium at constant volume will be –
A
N₂ and H₂ are formed in abundance
B
N₂, H₂ and NH₃ will have the same molar concentration
C
The production of ammonia increases
D
No change in the equilibrium
78
For the reaction H₂(g) + I₂(g) ⇌ 2HI(g) at 721 K, the value of equilibrium constant Kc is 50. When the equilibrium concentration of both H₂ & I₂ is 0.5 M, value of Kp under the same conditions will be –
A
0.02
B
0.2
C
50.0
D
50/RT
79
2.0 mol of PCl₅ were introduced in a vessel of 5.0 L capacity at a particular temperature. At equilibrium, PCl₅ was found to be 35% dissociated into PCl₃ and Cl₂. The value of Kc for the reaction is -
A
1.89
B
0.377
C
0.75
D
0.075
80
At 250° C, the vapour density of PCl₅ is Y (at equilibrium) and molar mass is Q (Initially). Its degree of dissociation is then equal to -
A
(Q − Y)/Y
B
(Y − Q)/Q
C
(Y − 2Q)/(2Q)
D
(Q − 2Y)/(2Y)
81
The reversible reaction [Cu(NH₃)₄]²⁺ + SO₃²⁻ ⇌ [Cu(NH₃)₃SO₃] + NH₃ is at equilibrium. What would not happen if ammonia is added –
A
[SO₃²⁻] would increase
B
[Cu(NH₃)₃SO₃] would increase
C
The value of equilibrium constant would not change
D
[Cu(NH₃)₄]²⁺ would increase
82
In Which of the following equilibria, the value of Kₚ is less than Kc -
A
H₂ + I₂ ⇌ 2HI
B
N₂ + 3H₂ ⇌ 2NH₃
C
N₂ + O₂ ⇌ 2NO
D
CO + H₂O ⇌ CO₂ + H₂
83
Dissociation of phosphorus pentachloride is favoured by –
A
High temperature and high pressure
B
High temperature and low pressure
C
Low temperature and low pressure
D
Low temperature and high pressure
84
When the equilibrium : 2NH₃ ⇌ N₂ + 3H₂ has been established, NH₃ is found to be 20% dissociated. The ratio of total number of moles at equilibrium to the moles of NH₃ at equilibrium is –
A
3/2
B
2/3
C
3/1
D
1/3
85
The value of Δng for the reaction : 2Hg(l) + Cl₂(g) ⇌ Hg₂Cl₂(s) is –
A
−1
B
+2
C
−2
D
0
86
On heating a mixture of SO₂Cl₂ and CO, two equilibria are simultaneously established : SO₂Cl₂(g) ⇌ SO₂(g) + Cl₂(g) CO(g) + Cl₂(g) ⇌ COCl₂(g) On adding more SO₂ at equilibrium what will happen ?
A
Amount of CO will decrease
B
Amount of SO₂Cl₂ and COCl₂ will increase
C
Amount of CO will remain unaffected
D
Amount of SO₂Cl₂ and CO will increase
87
The unit of equilibrium constant for the reaction H₂ + I₂ ⇌ 2HI is –
A
Mole⁻¹ litre
B
Mole⁻² litre
C
Mole litre
D
None
88
Which among the following conditions, increases the yield of the product in the equilibrium, 3A(g) + B(g) ⇌ 4C(g) + heat
A
Increase in pressure
B
Increase in volume
C
Increase in temperature
D
Decrease in temperature
89
The reaction in which the yield of the products can not be increased by the application of high pressure is –
A
PCl₃(g) + Cl₂(g) ⇌ PCl₅(g)
B
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
C
N₂(g) + O₂(g) ⇌ 2NO(g)
D
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
90
Which of the following is not favourable for formation of SO₃ ? 2SO₂(g) + O₂(g) ⇌ 2SO₃(g); ΔH = −188 KJ
A
High pressure
B
High temperature
C
Decreasing [SO₃]
D
Increasing [SO₂]
91
The ratio of Kp / Kc for the reaction : CO(g) + 1/2 O₂(g) ⇌ CO₂(g) is –
A
1.0
B
RT
C
1/√RT
D
(RT)¹ᐟ²
92
At 27°C, it was observed in the hydrogenation reaction, the pressure of H2 gas decreases from 10 atm to 2 atm in 10 mins. Calculate the rate of reaction in M min−1.
(Given: R = 0.08 lit atm K-1 mol-1 )
A
0.02
B
0.03
C
0.04
D
0.05
93
Kp will be equal to Kc under which of the following conditions for the reaction–
aA + bB ⇌ cC + dD
A
(a + b) > (c + d)
B
(a + b) − (c + d) = 0
C
(c + d) > (a + b)
D
(a + c) = (b + d)
94
On adding inert gas to the equilibrium PCl₅(g) ⇌ PCl₃(g) + Cl₂(g) at constant pressure. The degree of dissociation will remain –
A
Unchanged
B
Decreased
C
Increased
D
None of these
95
In Bodenstein experiment, one mol H₂ and two mol I₂ are taken initially in a one litre flask. If at equilibrium 0.5 mol H₂ are present, the equilibrium concentrations of I₂ and HI in mol l⁻¹ are –
A
0.5 , 1.0
B
1.0 , 0.5
C
1.5 , 1.0
D
1.5 , 0.5
96
At 250°C and 1 atmospheric pressure, the vapour density of equilibrium mixture obtained on dissociation of PCl₅ is 57.9. What will be the degree of dissociation of PCl₅ –
A
1.00
B
0.90
C
0.80
D
0.65
97
For the equilibrium reaction : 2HCl(g) ⇌ H₂(g) + Cl₂(g) the equilibrium constant is 1.0 × 10⁻⁵ what is the concentration of HCl if the equilibrium concentrations of H₂ and Cl₂ are 1.2 × 10⁻³ M and 1.2 × 10⁻⁴ M respectively –
A
12 × 10⁻² M
B
12 × 10⁻⁴ M
C
12 × 10⁻³ M
D
12 × 10⁴ M
98
The equilibrium constant for the reaction 2X(g) + Y(g) ⇌ 2Z(g) is 2.25. What would be the concentration of Y at equilibrium with 2.0 moles of X and 3.0 moles of Z in one litre vessel at equilibrium –
A
1.0 moles
B
2.25 moles
C
2.0 moles
D
4.0 moles
99
Consider the reaction, CaCO₃(s) ⇌ CaO(s) + CO₂(g); in closed container at equilibrium. What would be the effect of addition of CaCO₃ on the equilibrium concentration of CO₂ -
A
Increases
B
Decreases
C
Remains unaffected
D
Data is not sufficient to predict it
100
Mechanism of a hypothetical reaction X2 + Y2 → 2XY is given below :-
(i) X2 ⇌ X + X (fast)
(ii) X + Y2 → XY + Y (slow)
(iii) X + Y → XY (fast)
The overall order of the reaction will be :-
A
1
B
2
C
0
D
1.5
101
The equilibrium constant for the reaction Zn(s)+CO₂(g) ⇌ ZnO(s) + CO(g) is -
A
PCO/PCO₂
B
[ZnO]/[Zn]
C
PZnO PCO / PZn PCO₂
D
PZn PCO₂ / PZnO PCO₂
102
For the reaction, PCl₅(g) ⇌ PCl₃(g) + Cl₂(g), the forward reaction at constant temperature is favoured by - I. introducing inert gas at constant volume. II. introducing inert gas at constant pressure. III. decreasing pressure of the reaction mixture. IV. by adding PCl₃ to the reaction mixture.
A
I and II
B
II and III
C
I and III
D
III and IV
103
In A + B + Heat ⇌ C, then reaction is favoured at –
A
High temperature and high pressure
B
High temperature and low pressure
C
Low temperature and high pressure
D
Low pressure and low temperature
104
In what manner will increase of pressure affect the equation C(s) + H₂O(g) ⇌ CO(g) + H₂(g) -
A
Shift in the forward direction
B
Shift in the reverse direction
C
Increase in the yield of H₂
D
No effect
105
If K₁ = 4 × 10⁻³ for first gaseous reaction –
SO₂(g) + 1/2 O₂(g) ⇌ SO₃(g); K₁
2SO₃(g) ⇌ 2SO₂(g) + O₂(g); K₂ then K₂ will be –
A
8 × 10⁻³
B
6.25 × 10⁴
C
6.25 × 10⁸
D
8 × 10⁴
106
According to Law of Mass action, the rate of reaction is directly proportional to -
A
molarities of the reactants
B
normalities of the reactants
C
molalities of the reactants
D
mole fractions of the reactants
107
Which of the following equilibrium is not affected by pressure -
A
N₂(g) + O₂(g) ⇌ 2NO(g)
B
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
C
2O₃(g) ⇌ 3O₂(g)
D
2NO₂(g) ⇌ N₂O₄(g)
108
What is wrong about equilibrium state –
A
ΔG(equi) = 0
B
The reaction ceases at equilibrium
C
Equilibrium constant is independent of initial concentrations of reactants
D
Catalyst has no effect on equilibrium state
109
In the reaction, 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) + X cals, most favourable condition of temperature and pressure for greater yield of SO₃ are -
A
Low temperature and low pressure
B
High temperature and low pressure
C
High temperature and high pressure
D
Low temperature and high pressure
110
For the reaction : N₂O₃(g) ⇌ NO(g) + NO₂(g) ; total pressure = P, degree of dissociation = 50%. Then Kₚ would be –
A
3P
B
2P
C
P/3
D
P/2
111
A chemical reaction A ⇌ B is said to be in equilibrium when -
A
Complete conversion of A to B has taken place
B
Conversion of A to B is only 50% complete
C
Only 10% conversion of A to B has taken place
D
The rate of transformation of A to B is just equal to rate of transformation of B to A in the system
112
For the reaction : 2HI(g) ⇌ H₂(g) + I₂(g); the degree of dissociation (α) of HI(g) is related to equilibrium constant Kp by the expression
A
(1 + 2√Kp)/2
B
√(1 + 2Kp)/2
C
√(2Kp/(1 + 2Kp))
D
2√Kp/(1 + 2√Kp)
113
The value of KC for the reaction :
A + 3B → 2C is 0.5 at 400°C. Calculate the value of KP
A
1.64 × 10–4
B
1.64 × 10–6
C
1.64 × 10–5
D
1.64 × 10–3
114
The correct expression for equilibrium constant, Kc, for the reaction : H₂(g) + 1/2 O₂(g) ⇌ H₂O(g) is –
A
[H₂O]/([H₂][O₂]¹ᐟ²
B
PH₂O/(PO₂¹ᐟ²·PH₂)
C
[H₂O]/([H₂][O₂]¹ᐟ²)
D
PH₂O/(1/2 PO₂·PH₂)
115
The endothermic reaction MCO₃(s) ⇌ MO(s) + CO₂(g) is taking place in such a way that the vapour pressure of CO₂ is equal to atmospheric pressure. Which of the following is not correct ?
A
ΔG° = 0
B
Kp = 1
C
ΔG = 0
D
ΔH = 0
116
When 120 g acetic acid is reacted with 138 g ethyl alcohol, the amount of alcohol consumed is 30% of its initial concentration. The number of moles of acetic acid at equilibrium are –
A
1.1
B
2.1
C
1.7
D
0.9
117
An equilibrium mixture for the reaction 2H₂S(g) ⇌ 2H₂(g) + S₂(g) had 1 mole of H₂S, 0.2 mole of H₂ and 0.8 mole of S₂ in a 2 litre flask. The value of Kc in mol lit.⁻¹ is–
A
0.004
B
0.080
C
0.016
D
0.160
118
If in the reaction N₂O₄(g) ⇌ 2NO₂(g), α is the part of N₂O₄ which dissociates then the number of moles at equilibrium will be -
A
3
B
1
C
(1−α)²
D
(1 + α)
119
During thermal dissociation of gas, the vapour density -
A
Remains same
B
Will be increased
C
Will be decreased
D
Some times increases some times decreases
120
The figure shows the change in concentration of species A and B as a function of time. The equilibrium constant Kc for the reaction A(g) ⇌ 2B(g) is -
A
Kc > 1
B
K < 1
C
K = 1
D
data insufficient
121
Chemical equilibrium is dynamic in nature because –
A
The equilibrium in maintained quickly
B
Conc. of reactants and products become same at equilibrium
C
Conc. of reactants and products are constant but different
D
Both forward and backward reactions occur at equilibrium with same speed
122
In the reaction A(g) + B(g) ⇌ C(g), the backward reaction is favoured by -
A
Increase in pressure
B
Decrease in pressure
C
Neither increase nor decrease in pressure
D
Data unpredictable
123
In closed vessel PCl₅ undergoes thermal dissociation as – PCl₅ ⇌ PCl₃ + Cl₂, the mole fraction of PCl₃ at equilibrium is 0.4. The total pressure is 2.0 atmosphere. The partial pressure of Cl₂ at equilibrium is –
A
2.5
B
0.8
C
0.5
D
None
124
The equilibrium concentration of X, Y and YX₂ are 4, 2 and 2 mole L⁻¹ respectively for the equilibrium 2X(g) + Y(g) ⇌ YX₂(g). The value of Kc is -
A
0.625
B
0.0625
C
6.25
D
0.00625
125
In the study of the reaction – Cl₂ + PCl₃ ⇌ PCl₅ partial pressures of Cl₂, PCl₃ and PCl₅ at equilibrium are 0.1, 0.1 and 0.2 atm respectively at 250° C. At the same temperature, in another experiment on the same reaction, at equilibrium the partial pressures of PCl₃ and Cl₂ are half those in the first experiment. The partial pressure of the PCl₅ at equilibrium in the second experiment is –
A
One-fourth of the first
B
Half of the first
C
One-eighth of the first
D
One-third of the first
126
CaCO₃(s) ⇌ CaO(s) + CO₂(g) For above reaction, ΔG° (standard Gibb's free energy) will be :
A
ΔG° = −RT ln(1/PCO₂)
B
ΔG° = −RT ln PCO₂
C
ΔG° = −2RT ln PCO₂
D
none of these
Question Palette
Unattempted
Correct
Incorrect