#### Physical and Chemical Equilibrium Three Marks Questions

11th Standard

Reg.No. :
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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
10 x 3 = 30
1. The value of Kc for the following reaction at 717 K is 48.

2. The value of Kc for the reaction

3. One mole of H2 and one mole of I2 are allowed to attain equilibrium. If the equilibrium mixture contains 0.4 mole of HI. Calculate the equilibrium constant.

4. The equilibrium concentrations of NH3, N2 and H2 are 1.8 × 10-2 M, 1.2 × 10-2 M and 3 × 10-2 M respectively. Calculate the equilibrium constant for the formation of NH3 from N2 and H2. [Hint: M= mol lit-1]

5. For an equilibrium reaction Kp = 0.0260 at 25° C ΔH= 32.4 kJmol-1, calculate Kp at 37° C

6. For the reaction,
A2(g) + B2(g) ⇌ 2AB(g) ; ΔH is –ve.
the following molecular scenes represent different reaction mixture (A – green, B – blue)

i) Calculate the equilibrium constant KP and (KC).
ii) For the reaction mixture represented by scene (x), (y) the reaction proceed in which directions?
iii) What is the effect of increase in pressure for the mixture at equilibrium.

7. One mole of PCl5 is heated in one litre closed container. If 0.6 mole of chlorine is found at equilibrium, calculate the value of equilibrium constant.

8. For the reaction
SrCO3 (s) ⇌ SrO (s) + CO2(g),
the value of equilibrium constant KP = 2.2 × 10–4 at 1002 K. Calculate KC for the reaction.

9. To study the decomposition of hydrogen iodide, a student fills an evacuated 3 litre flask with 0.3 mol of HI gas and allows the reaction to proceed at 500o C. At equilibrium he found the concentration of HI which is equal to 0.05 M. Calculate KC and KP.

10. Oxidation of nitrogen monoxide was studied at 200o C with initial pressures of 1 atm NO and 1 atm of O2. At equilibrium partial pressure of oxygen is found to be 0.52 atm calculate KP value.