Final answer:
To find the pOH of a 0.1 M BCl solution after mixing 500 ml of 0.2 M BOH with 500 ml of 0.1 M HCl, more information on the reaction and dissociation constants is needed, as pOH depends on hydroxide ion concentration.
Step-by-step explanation:
The question asks to find the pOH of a 0.1 M BCl solution after mixing 500 ml of 0.2 M BOH (weak base) with 500 ml of 0.1 M HCl and being given that the pOH of the resulting buffer solution is 5. It's important to note that we cannot directly compare the pOH of a buffer solution with the pOH of a solution of 0.1 M BCl without considering the reaction that takes place when the weak base BOH is mixed with the strong acid HCl.
The strong acid will react with the weak base to form the conjugate acid BCl and water, which is a typical acid-base neutralization reaction. We do not have enough information provided to determine the pOH of the 0.1 M BCl solution, because pOH is determined by the concentration of hydroxide ions, and we do not know how the mixture affects the hydroxide ion concentration without more context about the reaction and the dissociation constants for the substances involved.