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

Solid carbon, CaO and CaCO3 are mixed and allowed to attain equilibrium at T K. CaCO3(s) CaO(s) + CO2(g) Kp1 = 0.08 atm C(s) + CO2(g) 2CO(g) Kp2 = 2 atm The partial pressure of CO is 10-1 atm

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

In a closed flask at 600 K, one mole of X2Y4(g) attains equilibrium as given below : X2Y4(g) 2XY2(g) At equilibrium, 75% X2Y4(g) was dissociated and the total pressure is 1 atm. The magnitude of rG (in kJ mol-1) at this temperature is . (Nearest Integer) (Given : R = 8.3 J mol-1 K-1; ln 10 = 2.3, log 2 = 0.3, log 3 = 0.48, log 5 = 0.69, log 7 = 0.84)

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 values of pressure equilibrium constant recorded at different temperatures for the following equilibrium reaction have been given below A(g) B(g) + C(g) array|c|c| 1T ( K-1) & 10 Kp \ 0.05 & 3.5 \ 0.06 & 2.5 \ 0.07 & 1.5 \ array The magnitude of H R calculated from the above data is . (Nearest integer)

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

The pH of a solution obtained by mixing 5 mL of 0.1 M NH4OH solution with 250 mL of 0.1 M NH4Cl solution is 10-2. (Nearest integer) Given: pKb(NH4OH) = 4.74 2 = 0.30 3 = 0.48 5 = 0.70

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

For the following reaction at 50 °C and at 2 atm pressure, 2N2O5(g) 2N2O4(g) + O2(g) N2O5 is 50% dissociated. The magnitude of standard free energy change at this temperature is x. x = J mol-1 [Nearest integer]. Given : R = 8.314 J mol-1 K-1, log 2 = 0.30, log 3 = 0.48, ln 10 = 2.303, °C + 273 = K

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

Consider the dissociation equilibrium of the following weak acid HA H+(aq) + A-(aq) If the pKa of the acid is 4, then the pH of 10 mM HA solution is . (Nearest integer) [Given: The degree of dissociation can be neglected with respect to unity]

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 two Group IV metal ions X2+ and Y2+. A solution containing 0.01 M X2+ and 0.01 M Y2+ is saturated with H2S. The pH at which the metal sulphide YS will form as a precipitate is . (Nearest integer) (Given: Ksp(XS) = 1 10-22 at 25 , Ksp(YS) = 4 10-16 at 25 , [H2S] = 0.1 M in solution, Ka1 Ka2(H2S) = 1.0 10-21, 2 = 0.30, 3 = 0.48, 5 = 0.70)

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

For the following gas phase equilibrium reaction at constant temperature, NH3(g) 1/2 N2(g) + 3/2 H2(g) if the total pressure is 3 atm and the pressure equilibrium constant (Kp) is 9 atm, then the degree of dissociation is given as (x 10-2 )-1/2. The value of x is . (nearest integer)

X2(g) + Y2(g) 2Z(g) X2(g) and Y2(g) are added to a 1 L flask and it is found that the system attains the above equilibrium at T(K) with the number of moles of X2(g), Y2(g) and Z(g) being 3, 3 and 9 mol respectively (equilibrium moles). Under this condition of equilibrium, 10 mol of Z(g) is added to the flask and the temperature is maintained at T(K). Then the number of moles of Z(g) in the flask when the new equilibrium is established is . (Nearest integer)

Dissociation of a gas A2 takes place according to the following chemical reaction. At equilibrium, the total pressure is 1 bar at 300 K. A2(g) 2A(g) The standard Gibbs energy of formation of the involved substances has been provided below: arraycc Substance & Gf /kJ mol-1 \ A2 & -100.00 \ A & -50.832 array The degree of dissociation of A2(g) is given by (x 10-2)1/2 where x = . (Nearest integer). [ Given : R = 8 J mol-1 K-1, 2 = 0.3010, 3 = 0.48 ] Assume degree of dissociation is not negligible.

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

The first and second ionization constants of H2X are 2.5 10-8 and 1.0 10-13 respectively. The concentration of X2- in 0.1 M H2X solution is 10-15 M. (Nearest Integer)

The equilibrium constant for decomposition of H2O(g) H2O(g) H2(g) + 12O2(g); G = 92.34 kJ mol-1 is 8.0 10-3 at 2300 K and total pressure at equilibrium is 1 bar. Under this condition, the degree of dissociation ( ) of water is 10-2 (nearest integer value). [Assume is negligible with respect to 1]

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