Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ as HB+ and C9H7N as B.)

Question

0.113 mol L−1 C9H7NHBr (aq) 0.104 mol L−1 HBr(aq) 0.122 mol L−1 NaOH(aq)
(a)Provide simple instructions for preparing 1.00 L of a solution having pH = 7.00 at 298 K. Your instructions should include the volumes of the solutions required.
(b) What is the buffer capacity of the resulting solution? (The buffer capacity is the number of moles of NaOH that must be added to 1.0 L of solution to raise the pH by one unit.)

Answer 1

OK. Then what does that incomplete sentence mean " 0.113 mol ...0.104 HBr....0.122 NaOH? That tid bit is just thrown in there with no explanation of what it has to do with the problem. That MAY be the way to calculate the concn of the acid and base; it should be obvious that we can't calculate the mols acid and base with just liters and no concns listed. mols = M x L. We have L but no molarities as it stands unless that incomplete sentence is supposed to convey that information.