264) In a buffer solution containing equal concentration of B⁻ and HB, the K_b for B⁻ is 10⁻¹⁰. The pH of buffer solution is:

265) Equal volumes of two solutions of NaOH, one having pH = 11 and the other having pH = 12, are mixed together. pH of the resultant solution will be:

266) If the pH of a Ba(OH)₂ solution is 11, the concentration of this solution is:

267) If K_sp of Ba(OH)₂ is 4 x 10⁻⁹, then the pH of saturated solution of Ba(OH)₂ is:

268) For the non equilibrium process, A + B → Products, the rate is first order with respect to A and second order with respect to B. If 1.0 mole each of A and B are introduced in 1 litre of vessel and the initial rate was 1.0 x 10^𕒶 mol⁄litre−sec. The rate (in mol litre⁻¹ sec⁻¹) when half of the reactants have been used?