Chemistry - Chemical Equilibrium Question Paper 1
Exam Duration: 45 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.
Which one of the following reactions has the least tendency to go to completion?
- (a)
\(2H_{2}(g)+O_{2}(g)\rightleftharpoons 2H_{2}O; \ K=1.7\times10^{27}\)
- (b)
\(N_{2}(g)+O_{2}(g)\rightleftharpoons 2NO;\ K=5.0\times 10^{-31}\)
- (c)
\(H_{2}(g)+C1_{2}(g)\rightleftharpoons 2HC1(g); \ K=3.2\times10^{16}\)
- (d)
\(2NOC1(g)\rightleftharpoons 2NO(g)+C1_{2}(g);\)
What is the unit of \(K_{c}\) for the following equilibria \(2NO(g)+C1_{2}\rightleftharpoons 2NOC1(g)\)
- (a)
\(mol\ l^{-1}\)
- (b)
\(l mol^{-1}\)
- (c)
\(l\ cm^{-1}\)
- (d)
no units
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)
\(K_{2}={1\over K_{1}}\)
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)
\(9.3 \times10^{-7} mol \ l^{-1}\)
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 \(mol^{2} \ l^{-2}\)
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 equilibrium constant for the reaction \(N_{2}+3H_{2}\rightleftharpoons 2NH_{3}\), is K. The equilibrium constant for the reation \(NH_{3}\rightleftharpoons {1\over2}N_{2}+{3\over2}H_{2}\) would be
- (a)
\(\sqrt{K}\)
- (b)
\(\sqrt{1/K}\)
- (c)
1/K
- (d)
\(1/K^{3}\)
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)
\(K_{1}-K_{2}\)
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)
\(8.8 \ mol \ l^{-1}\)
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
For which of the following reactions are the numerical values of \(K_{p}\) and \(K_{c}\) the same ?
- (a)
\(N_{2}(g)+3H_{2}(g)\rightleftharpoons 2NH_{3}(g)\)
- (b)
\(2NOC1(g)\rightleftharpoons 2NO(g)+C1_{2}(g)\)
- (c)
\(H_{2}(g)+I_{2}(g)\rightleftharpoons 2HI(g)\)
- (d)
\(H_{2}(g)+C1_{2}(g)\rightleftharpoons 2HC1\)
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)
\(5\times10^{-5} R^{-1}\)
The equilibrium constant in a reversible chemical reaction at a given temperature
- (a)
depends on the initial concentration of the reactants
- (b)
depends on the concentration of one of the produsts at equilibrium
- (c)
does not depend on the initial concentrations of reactants
- (d)
is not characteristic of the reaction
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
\(K_{c}=100 \) for the reaction \(2SO_{2}(g)+O_{2}(g)\rightleftharpoons 2SO_{3}(g)\) at \(100^{o}C\)
At equilibrium, if the number of moles of \(SO_{3}\) is equal to that of \(SO_{2}\)
- (a)
the number of moles \(O_{2}\) is equal to that of \(SO_{2}\)
- (b)
the number of moles \(O_{2}\) is equal to half of that of \(SO_{2}\)
- (c)
\([O_{2}]=0.10 M\)
- (d)
the number would have several values
The chemical reaction, \(A\rightleftharpoons B\) the system will be known to be in equilibrium when
- (a)
50% A changes to B
- (b)
A completely change to B
- (c)
Only 25% of A changes to B
- (d)
the rate of change of A to B and B to A on both the sides are same.
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
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
In which of the following reactions, increases in the volume at constant temperature do not affect the number of moles at equilibrium?
- (a)
\(2NH_{ 3 }\rightleftharpoons N_{ 2 }+3H_{ 2 }\)
- (b)
\(C(s)+\frac { 1 }{ 2 } O_{ 2 }(g)\longrightarrow CO(g)\)
- (c)
\(H_{ 2 }(g)+O_{ 2 }(g)\longrightarrow H_{ 2 }O_{ 2 }(g)\)
- (d)
None of the above
At constant temperature, the equilibrium constant (Kp) for the decomposition reaction \(N_{ 2 }O_{ 4 }(g)\rightleftharpoons 2NO_{ 2 }(g)\), is expressed by \(K_{ p }=\frac { (4x^{ 2 }p) }{ (1-x^{ 2 }) } \) where, p=pressure, x=extent of decomposition. Which one of the following statements is correct?
- (a)
Kp increases with increase of p
- (b)
Kp remains constant with change in p and x
- (c)
Kp increases with increase of x
- (d)
None of the above
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
In which of the following reactions, the equilibrium remains unaffected on addition of small amount of argon at constant volume?
- (a)
\(H_{ 2 }(g)+I_{ 2 }(g)\rightleftharpoons 2HI(g)\)
- (b)
\(PCl_{ 5 }(g)\rightleftharpoons 2PCl_{ 3 }(g)+Cl_{ 2 }(g)\)
- (c)
\(N_{ 2 }(g)+3H_{ 2 }(g)\rightleftharpoons 2NH_{ 3 }(g)\)
- (d)
The equilibrium will remain uneffected in all the three cases
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
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
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
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 equilibrium constant (Kc) for the reaction, \(N_{ 2 }(g)+O_{ 2 }(g)\longrightarrow 2NO(g)\), at temperature T is 4X10-4. The value of Kc for the reaction.
\(NO(g)\longrightarrow \frac { 1 }{ 2 } N_{ 2 }(g)+\frac { 1 }{ 2 } O_{ 2 }(g)\) at the same temperature is
- (a)
0.02
- (b)
2.5X102
- (c)
4X10-4
- (d)
50.0
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