Equilibrium

Consider the following reactions in which all the reactants and products are present in gaseous state 2xy x2 + y2 K1 = 2.5 105 xy + 12z2 xyz K2 = 5 10-3 The value of K3 for the equilibrium 12x2 + 12y2 + 12z2 xyz is :

1. 2.5 10-3
2. 2.5 103
3. 1.0 10-5
4. 5 10-3

One mole each of He and A(g) are taken in a 10 L closed flask and heated to 400 K to establish the following equilibrium. A(g) B(g) Kc for this reaction at 400 K is 4.0. The partial pressures (in atm) of He and B(g) are respectively (at equilibrium) (Assume He, A(g) and B(g) behave as ideal gases) (Given : R = 0.082 L atm K-1 mol-1)

1. 3.28, 2.624
2. 2.624, 3.28
3. 3.28, 0.656
4. 0.656, 6.56

Given is a concentrated solution of a weak electrolyte AxBy of concentration 'c' and dissociation constant 'K'. The degree of dissociation is given by :

1. [K cx+y-1xxyy ]x+y
2. ( Kcx+y-1xxyy ) 1x+y
3. ( cx+y-1xxyyK )x+y
4. ( cx+y-1xxyyK ) 1x+y

M3A2 is a sparingly soluble salt of molar mass y g mol-1 and solubility x g L-1. The ratio of the molar concentration of the anion ( A3-) to the solubility product of the salt is

1. 154 y4x4
2. y5108x4
3. 108 x5y5
4. 1108 y4x4

Arrange the following resultant mixtures in increasing order of their pH values Choose the correct answer from the options given below :

1. B < C < A
2. C < A < B
3. C < B < A
4. A < C < B

The reaction A(g) B(g) + C(g) was initiated with the amount 'a' of A(g). At equilibrium it is found that the amount of A(g) remaining is (a − x) at a total pressure of p. The equilibrium constant Kp of the reaction can be calculated from the expression :

1. x2a2 + x2 p
2. x2a2 - x2 p
3. a + x2x2 p
4. a2 - x2x2 p

At T(K), the equilibrium constant of A2(g) + B2(g) C(g) is 2.7 10-5. What is the equilibrium constant for 13A2(g) + 13B2(g) 13C(g) at the same temperature?

1. (2.7 10-5)3
2. 6 10-2
3. 2.7 10-5
4. 3 10-2

20 mL of a solution of acetic acid required 28.4 mL of 0.1 M NaOH for its neutralization. A solution (X) was prepared by mixing 20 mL of the above acetic acid and 14.2 mL of 0.1 M NaOH solution. What is the pH of the solution (X)? (pKa value of acetic acid is 4.75).

1. 7.0
2. 4.75
3. 3.5
4. 4.82

The solubility product constants of Ag2CrO4 and AgBr are 32x and 4y respectively at 298 K. The value of ( molarity of Ag2CrO4molarity of AgBr ) can be expressed as :

1. 2 [3]xy
2. 2 xy
3. xy
4. [3]x y

The first and second ionization constants of a weak dibasic acid H2A are 8.1 10-8 and 1.0 10-13 respectively. 0.1 mol of H2A was dissolved in 1 L of 0.1 M HCl solution. The concentration of HA- in the resultant solution is:

1. 0.1 M
2. 9.53 10-6 M
3. 8.1 10-8 M
4. 1.0 10-13 M

At 25°C, 20.0 mL of 0.2 M weak monoprotic acid HX is titrated against 0.2 M NaOH. The pH of the solution (a) at the start of the titration (when NaOH has not been added) and (b) when 10 mL of NaOH is added respectively, are : Given : Ka = 5 10-4 pKa = 3.3 1

1. array|c|c| (a) & (b) \ 0.7 & 2.0 \ array
2. array|c|c| (a) & (b) \ 2.0 & 3.3 \ array
3. array|c|c| (a) & (b) \ 1.1 & 2.2 \ array
4. array|c|c| (a) & (b) \ 3.0 & 2.2 \ array

Consider a weak base 'B' of pKb = 5.699. 'x' mL of 0.02 M HCl and 'y' mL of 0.02 M weak base 'B' are mixed to make 100 mL of a buffer of pH 9 at 25 . The values of 'x' and 'y' respectively are : [Given : 2 = 0.3010, 3 = 0.4771, 5 = 0.699]

1. arraycc x & y \ 42.7 & 57.3 array
2. arraycc x & y \ 14.3 & 85.7 array
3. arraycc x & y \ 85.7 & 14.3 array
4. arraycc x & y \ 11.1 & 88.9 array

Observe the following equilibrium in a 1 L flask. A(g) B(g) At T(K), the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A is added into the flask and heated to T(K) to establish the equilibrium again. The new equilibrium concentrations (in M) of A and B are respectively

1. 0.742, 0.557
2. 0.367, 0.275
3. 0.53, 0.4
4. 0.557, 0.418

Consider the following gaseous equilibrium in a closed container of volume 'V' at T(K). P2(g) + Q2(g) 2PQ(g) 2 moles each of P2(g), Q2(g) and PQ(g) are present at equilibrium. Now one mole each of 'P2' and 'Q2' are added to the equilibrium keeping the temperature at T(K). The number of moles of P2, Q2 and PQ at the new equilibrium, respectively, are

1. 2.56, 1.62, 2.24
2. 2.67, 2.67, 2.67
3. 1.21, 2.24, 1.56
4. 1.66, 1.66, 1.66

Consider the general reaction given below at 400 K x A(g) y B(g). The values of Kp and Kc are studied under the same condition of temperature but variation in x and y. (i) Kp = 85.87 and Kc = 2.586 appropriate units (ii) Kp = 0.862 and Kc = 28.62 appropriate units The values of x and y in (i) and (ii) respectively are :

1. array|c|c| (i) & (ii) \ 1,2 & 2,1 \ array
2. array|c|c| (i) & (ii) \ 1,3 & 2,1 \ array
3. array|c|c| (i) & (ii) \ 3,1 & 3,1 \ array
4. array|c|c| (i) & (ii) \ 4,1 & 4,1 \ array

Which of the following mixture gives a buffer solution with pH = 9.25 ? Given : pKb (NH4OH) = 4.75

1. 0.5 M NH4OH (0.2 L) + 0.2 M HCl (0.5 L)
2. 0.2 M NH4OH (0.5 L) + 0.1 M HCl (0.5 L)
3. 0.2 M NH4OH (0.4 L) + 0.1 M HCl (1 L)
4. 0.4 M NH4OH (1 L) + 0.1 M HCl (1 L)

For the reaction, N2O4 2NO2, graph is plotted as shown below. Identify correct statements. [figure] Choose the correct answer from the options given below :

1. C and E only
2. D and E only
3. A and D only
4. B and C only

An aqueous solution of HCl with pH 1.0 is diluted by adding equal volume of water (ignoring dissociation of water). The pH of HCl solution would (Given 2 = 0.30)

1. increase to 1.3
2. reduce to 0.5
3. increase to 2
4. remain same

In the following system, PCl5(g) PCl3(g) + Cl2(g) at equilibrium, upon addition of xenon gas at constant T & p, the concentration of

1. PCl5, PCl3 & Cl2 remain constant
2. PCl3 will increase
3. Cl2 will decrease
4. PCl5 will increase

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

1. Statement I is true but Statement II is false
2. Statement I is false but Statement II is true
3. Both Statement I and Statement II are true
4. Both Statement I and Statement II are false

If equal volumes of AB2 and XY (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of AY2 at 300 K ? (Given Ksp (at 300 K) for AY2 = 5.2 10-7)

1. 2.0 10-4 M AB2, 0.8 10-3 M XY
2. 2.0 10-2 M AB2, 2.0 10-2 M XY
3. 1.5 10-4 M AB2, 1.5 10-3 M XY
4. 3.6 10-3 M AB2, 5.0 10-4 M XY

Consider the following chemical equilibrium of the gas phase reaction at a constant temperature : A(g) B(g) + C(g) If p is the total pressure, Kp is the pressure equilibrium constant and is the degree of dissociation, then which of the following is true at equilibrium?

1. If Kp value is extremely high compared to p, becomes much less than unity
2. When p increases, increases
3. If p value is extremely high compared to Kp, 1
4. When p increases, decreases

At temperature T, compound AB2(g) dissociates as AB2(g) AB(g) + 12B2(g) having degree of dissociation x (small compared to unity). The correct expression for x in terms of Kp and p is:

1. Kp
2. [3] 2Kp2p
3. [3] 2Kpp
4. [4] 2Kpp

A weak acid HA has degree of dissociation x. Which option gives the correct expression of (pH - pKa)?

1. ( 1-xx )
2. 0
3. (1+2x)
4. ( x1-x )

Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K. If pressure of the system is increased 2 times, keeping temperature constant, then identify correct observation from following

1. Liquid phase disappears completely.
2. The amount of ice decreases.
3. The solid phase (ice) disappears completely.
4. Volume of system increases.

Arrange the following in increasing order of solubility product : Ca(OH)2, AgBr, PbS, HgS

1. PbS < HgS < Ca(OH)2 < AgBr
2. HgS < AgBr < PbS < Ca(OH)2
3. HgS < PbS < AgBr < Ca(OH)2
4. Ca(OH)2 < AgBr < HgS < PbS