Given:

Concentration of OH = [OH\(^-\)] = 0.001 M

At 25\(^0\)C, pH + pOH = 14

Hence, to find pH of KOH, we need to find the pOH first, then substitute the value into the equation above.

Recall, pOH = - Log [OH\(^-\)]

= - Log [0.001]

= - ( - 3)

pOH = 3

pH + pOH = 14

pH + 3 = 14

pH = 14 - 3 = 11

;. pH = 11 - option A