To find the pOH of an HCl solution with a concentration of 0.001 M, we first need to calculate the hydroxide ion concentration ([OH-]).
HCl is a strong acid and completely dissociates in water, yielding one hydrogen ion (H+) and one chloride ion (Cl-). Since the concentration of HCl is given as 0.001 M, the concentration of H+ is also 0.001 M.
In pure water, the concentration of H+ is equal to the concentration of OH-. Therefore, in this case, the concentration of OH- is also 0.001 M.
The pOH can be calculated using the formula:
pOH = -log[OH-]
Plugging in the value of [OH-] as 0.001 M:
pOH = -log(0.001) ≈ 3
So, the pOH of the 0.001 M HCl solution is approximately 3.