263) What is [H⁺] in mol⁄L of a solution that is 0.2M in CH₃COONa and 0.1M in CH₃COOH? K_a for CH₃COOH = 1.8 x 10⁻⁵

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: