Equilibrium

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

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)

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 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

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

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]

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)

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.

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]

One litre buffer solution was prepared by adding 0.10 mol each of NH3 and NH4Cl in deionised water. The change in pH on addition of 0.05 mol of HCl to the above solution is 10-2. (Nearest integer) Given : pKb of NH3 = 4.745 and 10 3 = 0.477

The pH of a 0.01 M weak acid HX (Ka = 4 10-10) is found to be 5. Now the acid solution is diluted with excess of water so that the pH of the solution changes to 6. The new concentration of the diluted weak acid is given as x 10-4 M. The value of x is (nearest integer)

x mg of Mg(OH)2 (molar mass = 58 g mol-1) is required to be dissolved in 1.0 L of water to produce a pH of 10.0 at 298 K. The value of x is mg. (Nearest integer) (Given : Mg(OH)2 is assumed to dissociate completely in H2O)

Consider the following equilibrium, CO(g) + 2H2(g) CH3OH(g) 0.1 mol of CO along with a catalyst is present in a 2 dm3 flask maintained at 500 K. Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of CH3OH is formed. The Kp is 10-3 (nearest integer). Given : R = 0.08 dm3 bar K-1 mol-1 Assume only methanol is formed as the product and the system follows ideal gas behaviour.