Here's how to determine the pOH of the HCl solution:

1. Find the pH:

* We know the concentration of H+ ions ([H+]) is 2.5 x 10^-5 M.

* pH = -log[H+]

* pH = -log(2.5 x 10^-5)

* pH ≈ 4.6

2. Use the relationship between pH and pOH:

* pH + pOH = 14

* pOH = 14 - pH

* pOH = 14 - 4.6

* pOH ≈ 9.4

Therefore, the pOH of the HCl solution is approximately 9.4.