JEE Main Chemistry - Chemical Equilibrium
Exam Duration: 60 Mins Total Questions : 30
Which one of the following is a reversible process ?
- (a)
mixing of gases by diffusion
- (b)
dissociation of a solute in pure solvent
- (c)
expansion of a gas in vacuum
- (d)
melting of ice without rise in temprature.
\(K_{p}\) for the reaction
\(A(g)+2B(g)\rightleftharpoons 2C(g)+D(s) \) is
- (a)
\([C^{2}]\over[A][B^{2}]\)
- (b)
\([C^{2}]\over[A][B]^{2}\)
- (c)
\([C^{2}][D]\over[A][B]^{2}\)
- (d)
\([A][B]^{2}\over[C^{2}][B]\)
Conisider the reaction \(A(g)+B(g)??\rightleftharpoons C(g)+D(g)\) Which occurs in one step. The specific rate constants are 0.25 and \(5.0\times 10^{13}\) for the forward and reverse reactions respectively. The value of equilibrium constant would be
- (a)
\(2.25\times10^{-6}\)
- (b)
\(5.0\times10^{-5}\)
- (c)
\(4.0\times10^{2}\)
- (d)
\(2.0\times10^{4}\)
Consider the reaction \(CaCO_{3}(s)\rightleftharpoons CaO(s)+CO_{2}(g)\) in a closed container at equilibrium at a fixed temperature. What will be the effect of adding more \(CaCO{3}\) on the equilibrium concentration of \(CO_{2}\)?
- (a)
It decreases
- (b)
It increases
- (c)
Cannot be predicated unless the value of \(K_{p}\) is given
- (d)
It remains unaffected
For the reaction \(A(g)+B(g)\rightleftharpoons C(g)\) the equilibrium partical pressures are \(P_{A}\)=0.15 atm, \(P_{B}\)+0.10 atm and \(P_{c}=0.30 \) atm. The volume was reduced so that reestablishing the equilibrium the partical pressure of A and B were doubled. The partical pressure of C would
- (a)
0.40 atm
- (b)
0.80 atm
- (c)
1.20 atm
- (d)
1.80 atm
4.0 moles of \(PC1_{5}\) dissociate at 760 K in a 2 litre flask \(PC1_{5}(g)??\rightleftharpoons PC1_{3}(g)+C1_{2}(g)\) At equilibrium constant would be
- (a)
\(1.0\times10^{-1}\)
- (b)
\(1.0\times10^{-4}\)
- (c)
\(1.0\times10^{-2}\)
- (d)
\(1.0\times10^{-3}\)
The ester, ethyl acetate, is formed by the reaction of ethanol and acetic acid and the equilibrium is represented as \(CH_{3}COOH(l)+C_{2}H_{5}OH(l)\rightleftharpoons CH_{3}COOC_{2}H_{5}(l)+H_{2}O(l)\) At 293 K, If one starts with 1.000 mole of acetic acid and 0.180 mole of ethanol, there is 0.171 mole of ethyl acetate in the final equilibrium mixture. The equilibrium would be
- (a)
3.919
- (b)
2.919
- (c)
4.919
- (d)
5.919
One more of \(O_{2}\) combines with 2 moles of \(SO_{3}\) in a container of volume V. At equilibrium it was observed that 2 moles of \(SO_{3}\) are produced. The value of k for the equilibrium would be
- (a)
\(x^{2}V/(1-x)^{3}\)
- (b)
\(4x^{2}/(2-x)^{2}(1-x)\)
- (c)
\((1-x)^{3}/x^{2}V\)
- (d)
\(x/(1+x)V\)
Under equilibrium conditions the amount of \(SO_{3}\) in a three-litre vessel was found to be 8g. Its equilibrium concentration could be
- (a)
\(0.8 \ mol \ l^{-1}\)
- (b)
\(0.33 \ mol \ l^{-1}\)
- (c)
\(3.3 \ mol \ l^{-1}\)
- (d)
\(8.8 \ mol \ l^{-1}\)
The vapour density of \(PCL_{5}\) when in equilibrium with its dissociation products was found to be 90. The degree of dissociation of \(PCL_{5}\) would be
- (a)
0.058
- (b)
0.158
- (c)
0.246
- (d)
0.264
At \(490^{o}\)C, the equilibrium constant for the synthesis of HI is 50, the value of K for dissociation of HI will be
- (a)
0.02
- (b)
0.2
- (c)
2.0
- (d)
20.00
If \(K_{p}\) for a reaction \(A(g)+2B(g)A+B\rightleftharpoons 3C(g)+D(g)\) is 0.05 atm at 1000 K, its \(K_{c}\) in terms of R will be
- (a)
2,0000 R
- (b)
0.02 R
- (c)
\(5\times10^{-15}\) R
- (d)
\(5\times10^{-5} R^{-1}\)
Eight moles of \(A_{3}B\) are introduced into an evacuated vessel of volume one litre. \(A_{3}B\) dissociates as \(2A_{3}B??\rightleftharpoons 3A_{2}(g)+B_{2}(g)\) At equilibrium 2 moles of \(B_{2}\) are present equilibrium constant could be
- (a)
72.0 \(mol^{2} \ l^{-2}\)
- (b)
36.0 \(mol^{2} \ l^{-2}\)
- (c)
3.0 \(mol^{2} \ l^{-2}\)
- (d)
27.0 \(mol^{2} \ l^{-2}\)
For the following system in equilibrium \(A(g)+B(g)\begin{matrix} { T }^{ o }C \\ \rightleftharpoons \end{matrix}2c(g); \ \triangle H=-+ve\)
- (a)
an increase in T will increase equilibrium constant
- (b)
an increase in T will decrease equilibrium constant
- (c)
an increase in P will increase equilibrium constant
- (d)
an increase in P will decrease equilibrium constant
The equilibrium constant expression for a gaseous reaction is
\(K_{c}={[NH_{3}]^{4}[O_{2}]^{5}\over[NO]^{4}[H_{2}O]^{6}}\)
The balance chemical equation corresponding to this expression would be
- (a)
\(4NO + 6H_{2}O\rightarrow4NH_{3}+5O_{2}\)
- (b)
\(4NH_{3}+5O_{2}\rightarrow4NO+6H_{2}O\)
- (c)
\(5NH_{3}+4O_{2}\rightarrow6NO+4H_{2}O\)
- (d)
None of these
For the reaction \(CH_{4}(g)+2H_{2}O(g)??\rightleftharpoons CS_{2}(g)+4H_{2}(g)\) at 1173 K the magnitude of the equilibrium constant \(K_{c}\)=3.6. For the following given composition
\([CH_{4}]=1.078 M; [H_{2}S]=1.20 M;[CS_{2}]=0.90 M, [H_{2}]=1.78 M\)
- (a)
the reaction is at equilibrium
- (b)
moves in forward direction
- (c)
move in backward direction
- (d)
nothing can be said.
In an equilibrium A+B\(\rightleftharpoons \) C+D, A and B are mixed in a vessel at temperature T. The initial concetration of A os twice the initial concentration of B. After the equilibrium has reached, concentration of C becomes thrice the equilibrium concentration of C becomes thrice the equilibrium concentration of B. The value of \(K_{c}\) for the above reaction would be
- (a)
1.0
- (b)
1.2
- (c)
1.6
- (d)
1.8
A sample of pure \(PC1_{3}\) was introduces into an evacuated vessel at 473 K. After equilibrium was attained, concentration of \(PC1_{3}\) was found to be \(0.5\times 10^{-1} mol L^{-1}\). The value of \(K_{c}\) is \(8.3\times10^{-13}\), the concentration of \(PC1_{3}\) at equilibrium would be
- (a)
0.01 \(mol L^{-1}\)
- (b)
0.02 \(mol L^{-1}\)
- (c)
0.03 \(mol L^{-1}\)
- (d)
0.04 \(mol L^{-1}\)
The value of \(K_{p}\) for the reaction given below at 1073 K is 167.
\(CaCO_{3}(s)\rightleftharpoons CaO(s)+CO_{2}(g)\) The value of \(K_{c}\) for the above reaction would be approximately
- (a)
2.0
- (b)
3.0
- (c)
4.0
- (d)
5.0
Change in volume of the system does not after the number of moles in which of the following equilibriums ?
- (a)
\(N_{2}(g)+O_{2}(g)\rightleftharpoons 2NO\)
- (b)
\(PCL_{5}(g)\rightleftharpoons PCL_{3}(g)+CL_{2}(g)\)
- (c)
\(N_{2}(g)+3H_{2}(g)\rightleftharpoons 2NH_{3}\)
- (d)
\(SO_{2}C1_{2}(g)\rightleftharpoons SO_{2}(g)+C1_{2}(g)\)
Which of the following is not general characteristic of equilibrium involving physical processes?
- (a)
Equilibrium is possible only in a closed system at a given temperature.
- (b)
All measurable properties of the system remain constant
- (c)
All the physical processes stop at equilibrium
- (d)
The opposing processes occur at the same rate and there is dynamic but stable condition.
In any chemical reaction, equilibrium is supposed to be attain when
- (a)
mutual opposite reactions start
- (b)
concentration of reactants and resulting products are equal
- (c)
concentration of reactants and resulting products are equal
- (d)
the temperature of mutual opposite reactions become equal
We know that relationship between Kc and Kp is Kp=Kc(RT)\(\Delta n\) What would be the value \(\Delta n\) of for the reaction?
\(NH_{ 4 }CL(s)\rightleftharpoons NH_{ 3 }(g)+HCl(g)\)
- (a)
1
- (b)
0.5
- (c)
1.5
- (d)
2
Consider the reaction, \(N_{ 2 }(g)+3H_{ 2 }(g)\rightleftharpoons 2NH_{ 3 }(g)\). Which of the following is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?
- (a)
K will remain same
- (b)
K will decrease
- (c)
K will increase
- (d)
K will increase initially and decrease when pressure is very high
For a system in equilibrium, \(\Delta G=0\) under conditions of constant
- (a)
temperature and pressure
- (b)
energy and volume
- (c)
temperature and energy
- (d)
pressure and volume
In the thermal decomposition of potassium chlorate given as \(2KClO_{ 3 }\longrightarrow 2KCl+3O_2\); Law of mass action
- (a)
Can be applied
- (b)
cannot be applied
- (c)
can be applied at low temperature and pressure
- (d)
can be applied at high temperature and pressure
One mole of nitrogen and three moles of hydrogen are mixed in a litre container. If 0.25 percent of nitrogen is converted to ammonia by the following reaction \(N_{ 2 }(g)+3H_{ 2 }(g)\rightleftharpoons 2NH_{ 3 }(g)\) Calculate the equilibrium constant (Kc) in concentration units.
- (a)
1.49X10-5 L2mol-2
- (b)
1.49X105L2 mol-2
- (c)
1.19X10-5 L2 mol-2
- (d)
1.19X105L2mol-2
The partial pressure of B is found to be one fourth of the partial pressure of A. For a reaction, \(A(g)\rightleftharpoons B(g)\). The value of \(\Delta G^o\) of the reaction \(A\rightarrow B\) will be
- (a)
RT ln 4
- (b)
-RT ln 4
- (c)
2.303RT ln 4
- (d)
-2.303RT ln 4
What is the equilibrium constant, K for the following reaction at 400K?
\(2NOCl(g)\rightleftharpoons 2NO(g)+Cl_{ 2 }(g)\); \(\Delta H=77.2kJmol^{-1}\) and \(\Delta S=122JK^{-1}mol^{-1}\) at 400K.
- (a)
-3.708
- (b)
1.95X10-4
- (c)
2.8X104
- (d)
1.67X10-5
For the reaction, \(2NO_{ 2 }(g)\rightleftharpoons 2NO(g)+O_{ 2 }(g)\) [Kc=1.8X10-6 at 184oC and R=0.00831kJ/(mol K)] when Kp and Kc are compared at 184oC, it is found that
- (a)
whether Kp is greater than, less than or equal to Kc depends upon the total gas pressure
- (b)
Kp=Kc
- (c)
Kp is less than Kc
- (d)
Kp is greater than Kc