13 questions from 2026
In a closed flask at \( 600 \, \mathrm{K} \), one mole of \( \mathrm{X_2Y_4(g)} \) attains equilibrium as given below:
\( \mathrm{X_2Y_4(g)} \rightleftharpoons 2\mathrm{XY_2(g)} \)
At equilibrium, \( 75\% \) \( \mathrm{X_2Y_4} \) was dissociated and the total pressure is \( 1 \, \mathrm{atm} \). The magnitude of \( \Delta_{\mathrm{f}}G^{\ominus} \) (in \( \mathrm{kJ\, mol^{-1}} \)) at this temperature is _________. (Nearest Integer)
(Given: \( R = 8.3 \, \mathrm{J\, mol^{-1}\, K^{-1}} \); \( \ln 10 = 2.3 \), \( \log 2 = 0.3 \), \( \log 3 = 0.48 \), \( \log 5 = 0.69 \), \( \log 7 = 0.84 \))
For the following reaction at \( 50^{\circ}\text{C} \) and at \( 2 \, \text{atm} \) pressure,
\( 2\mathrm{N_2O_5(g)} \rightleftharpoons 2\mathrm{N_2O_4(g)} + \mathrm{O_2(g)} \)
\( \mathrm{N_2O_5} \) is \( 50\% \) dissociated.
The magnitude of standard free energy change at this temperature is \( x \). \( x = \_\_\_\_\_\_ \, \text{J mol}^{-1} \) [Nearest integer].
Given : \( R = 8.314 \, \text{J mol}^{-1}\text{K}^{-1} \), log \( 2 = 0.30 \), log \( 3 = 0.48 \), \( \ln 10 = 2.303 \), \( ^{\circ}\text{C} + 273 = \text{K} \)
Solid carbon, \( \mathrm{CaO} \) and \( \mathrm{CaCO_3} \) are mixed and allowed to attain equilibrium at \( T \ \mathrm{K} \).
\( \mathrm{CaCO_3(s)} \rightleftharpoons \mathrm{CaO(s)} + \mathrm{CO_2(g)}; \ K_{p1} = 0.08 \ \mathrm{atm} \)
\( \mathrm{C(s)} + \mathrm{CO_2(g)} \rightleftharpoons 2\mathrm{CO(g)}; \ K_{p2} = 2 \ \mathrm{atm} \)
The partial pressure of \( \mathrm{CO} \) is ______ \( \times 10^{-1} \) \( \mathrm{atm} \).
For the following gas phase equilibrium reaction at constant temperature, \( \mathrm{NH_3(g)} \rightleftharpoons \dfrac{1}{2}\mathrm{N_2(g)} + \dfrac{3}{2}\mathrm{H_2(g)} \) if the total pressure is \( \sqrt{3} \, \text{atm} \) and the pressure equilibrium constant \( (K_p) \) is \( 9 \, \text{atm} \), then the degree of dissociation is given as \( (x \times 10^{-2})^{1/2} \). The value of \( x \) is _______. (Nearest integer)
At \( T(\mathrm{K}) \), the equilibrium constant of \( \mathrm{A_2(g)} + \mathrm{B_2(g)} \rightleftharpoons \mathrm{C(g)} \) is \( 2.7 \times 10^{-5} \). What is the equilibrium constant for \( \frac{1}{3}\mathrm{A_2(g)} + \frac{1}{3}\mathrm{B_2(g)} \rightleftharpoons \frac{1}{3}\mathrm{C(g)} \) at the same temperature?
Consider the general reaction given below at \( 400 \, \text{K} \).
\( xA(g) \rightleftharpoons yB(g) \)
The values of \( K_p \) and \( K_c \) are studied under the same condition of temperature but variation in \( x \) and \( y \).
(i) \( K_p = 85.87 \) and \( K_c = 2.586 \) appropriate units
(ii) \( K_p = 0.862 \) and \( K_c = 28.62 \) appropriate units
The values of \( x \) and \( y \) in (i) and (ii) respectively are:
At the transition temperature \( T \), \( A \rightleftharpoons B \) and \( \Delta G^{0} = 105 - 35 \log T \) where A and B are two states of substance X. The transition temperature in \( ^{\circ}\mathrm{C} \) when pressure is \( 1 \, \mathrm{atm} \) is _______. (Nearest integer)
Consider the following reactions in which all the reactants and products are present in gaseous state.
\( 2\,\mathrm{XY} \rightleftharpoons \mathrm{X_2} + \mathrm{Y_2};\ K_1 = 2.5 \times 10^{5} \)
\( \mathrm{XY} + \tfrac{1}{2}\mathrm{Z_2} \rightleftharpoons \mathrm{XYZ};\ K_2 = 5 \times 10^{-3} \)
The value of \( K_3 \) for the equilibrium \( \tfrac{1}{2}\mathrm{X_2} + \tfrac{1}{2}\mathrm{Y_2} + \tfrac{1}{2}\mathrm{Z_2} \rightleftharpoons \mathrm{XYZ} \) is:
When \\( 0.25 \\) moles of a non-volatile, non-ionizable solute was dissolved in \\( 1 \\) mole of a solvent the vapor pressure of solution was \\( x \\) % of vapor pressure of pure solvent. What is \\( x \\)%?
\( X_2(g) + Y_2(g) \rightleftharpoons 2Z(g) \)
\( X_2(g) \) and \( Y_2(g) \) are added to a \( 1 \, \text{L} \) flask and it is found that the system attains the above equilibrium at \( T(K) \) with the number of moles of \( X_2(g) \), \( Y_2(g) \) and \( Z(g) \) being \( 3 \), \( 3 \) and \( 9 \) mole 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\( \))
Consider the following gaseous equilibrium in a closed container of volume \( 'V' \) at \( T(\text{K}) \).
\( \mathrm{P_2(g) + Q_2(g) \rightleftharpoons 2PQ(g)} \)
\( 2 \) moles each of \( \mathrm{P_2(g)} \), \( \mathrm{Q_2(g)} \) and \( \mathrm{PQ(g)} \) are present at equilibrium. Now one mole each of \( \mathrm'{P_2}' \) and \( \mathrm'{Q_2}' \) are added to the equilibrium keeping the temperature at \( T(\text{K}) \). The number of moles of \( \mathrm{P_2} \), \( \mathrm{Q_2} \) and \( \mathrm{PQ} \) at the new equilibrium, respectively, are:
One mole each of \\( \\mathrm{He} \\) and \\( \\mathrm{A(g)} \\) are taken in a \\( 10 \\, \\mathrm{L} \\) closed flask and heated to \\( 400 \\, \\mathrm{K} \\) to establish the following equilibrium.
\\( \\mathrm{A(g)} \\rightleftharpoons \\mathrm{B(g)} \\)
\\( K_c \\) for this reaction at \\( 400 \\, \\mathrm{K} \\) is \\( 4.0 \\). The partial pressure (in atm) of \\( \\mathrm{He} \\) and \\( \\mathrm{B(g)} \\) are respectively (at equilibrium).
(Assume \\( \\mathrm{He} \\, \\mathrm{A(g)} \\) and \\( \\mathrm{B(g)} \\) behave as ideal gases)
(Given: \\( R = 0.082 \\, \\text{L atm K}^{-1} \\, \\text{mol}^{-1} \\))
Dissociation of a gas \( \mathrm{A_{2}} \) takes place according to the following chemical reaction. At equilibrium, the total pressure is \( 1 \,\mathrm{bar} \) at \( 300 \,\mathrm{K} \). \( \mathrm{A_{2}(g)} \rightleftharpoons 2\,\mathrm{A(g)} \) The standard Gibbs energy of formation of the involved substances has been provided below:
The degree of dissociation of \( \mathrm{A_{2}(g)} \) is given by \( \left(x \times 10^{-2}\right)^{1/2} \) where \( x = \) ____ . (Nearest integer).
[Given: \( R = 8 \,\mathrm{J\,mol^{-1}\,K^{-1}} \), \( \log 2 = 0.3010 \), \( \log 3 = 0.48 \) ]
Assume degree of dissociation is not negligible.
