Chemistry - Chemical Equilibrium
Exam Duration: 45 Mins Total Questions : 30
For the following two equilibria
\(SO_{2}(g)+1/2O_{2}(g)\rightleftharpoons SO_{3}(g); K_{1}\)
\(2SO_{3}(g)\rightleftharpoons 2SO_{2}(g)+O_{2}(g); K_{2}\)
The values of equilibrium constants are related by
- (a)
\(K_{2}=K_{1}^{2}\)
- (b)
\(K_{2}+{1\over K^{2}_{1}}\)
- (c)
\(K_{2}=K_{1}\)
- (d)
\(K_{2}={1\over K_{1}}\)
1 mole of \(H_{2}O\) and I mole of CO are taken in a 10 litre vessel and heated to 275 K. At equilibrium, 40 percent of water (by mass) reacts with CO according to the equation.\(H_{2}O(g)+CO(g)\rightleftharpoons H_{2}(g)+ CO(g)\) The equilibrium constant. for the reaction would be
- (a)
0.6
- (b)
6.6
- (c)
0.44
- (d)
0.4
The equilibrium constant at 298 K for \(Cu(s)+2Ag(aq)\rightleftharpoons Cu^{2}(aq)+2Ag(s)\) is \(2.0 \times 10^{15}\). In a solution, the concentration of \(Cu^{2+}\) ions is \(1.8\times10^{-2} mol \ l^{-1}\), and the concentration of \(Ag^{+} \) ions \(3.0 \times 10^{-19}\) mol \(l^{-1}\). The above system under above condition
- (a)
Will move in forward direction
- (b)
Will move in backward direction
- (c)
will remain in equilibrium
- (d)
it cannot be predicted
At 700 k, the equilibrium constant \(K_{p}\), for the reaction \(2SO_{3}(g)\rightleftharpoons 2SO_{2}(g)+O_{2}(g)\) is \(1.80\times10^{-3}\) kPa. The value of \(k_{c}\) for the above reaction at the same temperature in moles per litre would be
- (a)
\(1.1 \times10^{-7} mol \ l^{-1}\)
- (b)
\(31.1 \times10^{-7} mol \ l^{-1}\)
- (c)
\(6.2 \times10^{-7} mol \ l^{-1}\)
- (d)
\(9.3 \times10^{-7} mol \ l^{-1}\)
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
Two moles of \(NH_{3}\) gas are introduced into a previously evacuated one litre vessel in which it partically dissociate at high temperature as :\(2NH_{3}(g)\rightleftharpoons N_{2}(g)+H_{2}(g)\) At equilibrium, one mole of \(NH_{3}(g)\) remains. The value of \(K_{c}\) is
- (a)
3/4 \(mol^{2} \ l^{2}\)
- (b)
27/16 \(mol^{2} \ l^{-2}\)
- (c)
3/2 \(mol\ l^{-2}\)
- (d)
27/64 \(mol^{2} \ l^{-2}\)
Which of the following mixtures is at equilibrium at constant temperature if \(K_{p}=3\) for the equilibrium : \(2NH_{3}=N_{2}(g)+3H_{2}(g)\) Partial Pressures of various gases are:
- (a)
\(P_{NH_{3}} \ \ \ \ \ P_{N_{2}} \ \ \ \ \ P_{H_{2}}\) (in atm)
1 1.5 1
- (b)
\(P_{NH_{3}} \ \ \ \ \ P_{N_{2}} \ \ \ \ \ P_{H_{2}}\) (in atm)
3 3 2
- (c)
\(P_{NH_{3}} \ \ \ \ \ P_{N_{2}} \ \ \ \ \ P_{H_{2}}\) (in atm)
4 6 2
- (d)
\(P_{NH_{3}} \ \ \ \ \ P_{N_{2}} \ \ \ \ \ P_{H_{2}}\) (in atm)
6 1 2
The equilibrium constant K for the reaction \(N_{2}+3H_{2}??\rightleftharpoons 2NH_{3}\) is \(1.64\times10^{-14}\) and \(400^{o}C.\) The equilibrium constant at \(500^{o}C.\) would be: [given, the heat of reaction in this range is -25140 cal and R=1.987 cal]
- (a)
\(1.44\times10^{-5}\)
- (b)
\(14.4\times10^{-5}\)
- (c)
\(1.64\times10^{-4}\)
- (d)
\(5.76\times10^{-3}\)
The equilbrium constant at a certain temperature for the reactions \(H_{2}+1/2 \ S_{2}\rightarrow \ H_{2}S\) and \(H_{2}+Br_{2}\rightarrow2HBr\) are \(K_{1}\) and \(K_{2}\) respectively. The value of K for the reaction \(Br_{2}+H_{2}S\rightarrow2HBr+1/2 \ S_{2}\) would be
- (a)
\(K_{1}/K_{2}\)
- (b)
\(K_{2}/K_{1}\)
- (c)
\(K_{1}\times K_{2}\)
- (d)
\(K_{1}-K_{2}\)
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
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 reaction \(PCL_{5}\)\(\rightleftharpoons \)\(PCL_{3}(g)+CL_{2}(g)\)
- (a)
\(K_{p}=K_{c}\)
- (b)
\(K_{p}=K_{c}\) \((RT)^{-1}\)
- (c)
\(K_{p}=K_{c}\)\((RT)\)
- (d)
\(K_{p}=K_{c}\)\((RT)^{-2}\)
For a chemical equilibrium \(A(g)+B(g)\begin{matrix} 1\quad atm \\ \rightleftharpoons \\ { 400 }^{ o }C \end{matrix} \ C(g) \ - \ Q \ cal\)
- (a)
\(K_{p}=K_{c}\)
- (b)
\(K_{p}>K_{c}\)
- (c)
\(K_{p}
- (d)
\(K_{c}\) is independent of temperature
For the equilibrium \(A+B\rightleftharpoons C+D;K_{c}=100\) at Equi.
- (a)
[C][D]=[A][B]
- (b)
[C]=[A] and [B]=[D]
- (c)
[A][B]=0.01\(\times\)[C][D]
- (d)
[A]=[B]=[C]=[D]=10 mol
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 equilibrium constant in a reversible reaction at specified temperature
- (a)
does not depend on the initial concentrations
- (b)
depend on the initial concentrations of the reactants
- (c)
depend on the concentrations of the products at equilibrium
- (d)
is not characteristic of the reaction
The unit of equilibrium constant, K for the reaction, \(A+B\rightleftharpoons C\) would be
- (a)
mol L-1
- (b)
mol L
- (c)
mol-1 L
- (d)
\(1\over mol \ L\)
For the reaction Fe(s)+S(s)\(\rightleftharpoons \)FeS(s); the expression for equilibrium constant is
- (a)
\(\frac { \begin{bmatrix} FeS \end{bmatrix} }{ \begin{bmatrix} Fe \end{bmatrix}\begin{bmatrix} S \end{bmatrix} } \)
- (b)
\(\frac { { \begin{bmatrix} Fe \end{bmatrix}\begin{bmatrix} S \end{bmatrix} } }{ { \begin{bmatrix} FeS \end{bmatrix} } } \)
- (c)
\(\begin{bmatrix} Fe \end{bmatrix}\begin{bmatrix} S \end{bmatrix}\begin{bmatrix} FeS \end{bmatrix}\)
- (d)
None of these
Equilibrium constant K1 and K2 for the following chemical equilibria \(NO(g)+\frac { 1 }{ 2 } O_{ 2 }(g)\rightleftharpoons NO_{ 2 }(g)\) and, \(2NO_{ 2 }(g)\rightleftharpoons 2NO(g)+O_{ 2 }(g)\) are related as
- (a)
\(K_1={1\over K_2}\)
- (b)
\(K_2={1\over K_1}\)
- (c)
\(K_2={1\over K_1^2}\)
- (d)
\(K_1={1\over K_2^2}\)
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
The decomposition of N2O4 to NO2 is carried out at 280K in chloroform. When equilibrium has been established, 0.2 mole of N2O4 and 2X10-3 mole of NO2 are present in 2L solution. The equilibrium constant for reaction, \(N_{ 2 }O_{ 4 }\rightleftharpoons 2NO_{ 2 }\) is
- (a)
1X10-6
- (b)
1X10-3
- (c)
1X10-4
- (d)
1X10-5
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 reaction, \(2SO_{ 2 }(g)+O_{ 2 }(g)\rightleftharpoons 2SO_3(g)\) is carried out in 1dm3 and 2dm3 vessels, respectively. The ratio of the reaction velocities will be
- (a)
1:4
- (b)
4:1
- (c)
1:8
- (d)
8:1
According to Le-Chatelier's principle, if heat is given to solid-liquid system, then
- (a)
quantity of solid will reduce
- (b)
quantity of solid will increase
- (c)
temperature will increase
- (d)
temperature will decrease
In Haber's process, 30L of dihydrogen and 30L of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the aforesaid condition at the end?
- (a)
10L NH3, 25L N2, 15 L H2
- (b)
20L NH3, 20L N2, 20L H2
- (c)
20L NH3, 25L N2, 15L H2
- (d)
20L NH3, 10L N2, 30L H2
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, \(SO_{ 2 }(g)+\frac { 1 }{ 2 } O_{ 2 }(g)\rightleftharpoons SO_{ 3 }(g)\) If \(K_p=K_c(RT)^x\) where, the symbols have usual meaning then the value of x is (assuming ideality)
- (a)
-1
- (b)
\(-{1\over2}\)
- (c)
\(1\over 2\)
- (d)
1
The incorrect expression among the following is
- (a)
\({\Delta G_{syatem}\over \Delta S_{total}}=-T\)
- (b)
In isothermal process, \(w_{reversible}=-nRT \ In \ {V_f\over V_i}\)
- (c)
In \(K^o={{\Delta H^o}-{T\Delta S^o}\over RT}\)
- (d)
\(K^o=exp(-\Delta G^o/RT)\)
For the reaction \(CO(g)+Cl_2(g)\rightleftharpoons COCl_2(g)\) the Kp/Kc is equal to
- (a)
1/RT
- (b)
RT
- (c)
\(\sqrt {RT}\)
- (d)
1.0
Consider the reaction equilibrium \(2SO_{ 2 }(g)+O_{ 2 }(g)\rightleftharpoons 2SO_{ 3 }(g);\Delta H^{ o }=-198kJ\) on the basis of Le-Chatelier's principle, the condition favourable or the forward reaction is
- (a)
lowering of temperature as well as pressure
- (b)
increasing temperature as well as pressure
- (c)
lowering the temperature and increasing the pressure
- (d)
any value of temperature and pressure