55. A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of NH4 is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8 × 10–5, what is the pH of this solution?
(1) 8.73 (2) 9.08
(3) 9.43 (4) 11.72
56. Two gases A and B having the same volume diffuse through a porous partition in 20 and 10 seconds respectively.The molecular mass of A is 49 u. Molecular mass of B will be
57. Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?
(1) q = 0, ΔT < 0, w ≠ 0 (2) q = 0, ΔT ≠ 0, w = 0
(3) q ≠ 0, ΔT = 0, w = 0 (4) q = 0, ΔT = 0, w = 0
58. For the reaction N2(g) + O2(g) ⇌ 2NO(g) , the equilibrium constant is K1. The equilibrium constant is K2 for the reaction 2NO(g) + O2(g)⇌ 2NO2(g) . What is K for the reaction NO (g) ½ N2 (g) ⇌ O2 (g)?
62. Standard electrode potential for Sn4+ / Sn2+ couple is +0.15 V and that for the Cr3+ / Cr couple is –0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be
(1) +1.83 V (2) +1.19 V
(3) +0.89 V (4) +0.18 V
63. A gaseous mixture was prepared by taking equal mole of CO and N2. If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen (N2) in the mixture is