pOH can be calculated by the negative logarithm of [OH⁻] . pOH = -log [OH⁻] pH scale is used to determine how acidic/ neutral or basic a solution is. By knowing the pOH the pH can be calculated, as; pH + pOH = 14 pH = 14 - pOH dissociation of Ba(OH)₂ is as follows; Ba(OH₂) ---> Ba²⁺ + 2OH⁻ 1 mol Ba(OH₂) dissociates into 2 OH⁻ moles Therefore molarity of OH⁻ is twice as much as the molarity of Ba(OH₂). [OH⁻] = 2 x 2.80 M = 5.6 M pOH = -log 5.6 = -0.75 pH = 14 - - 0.75 = 14.75 when the pOH is a negative value this means that the pH is greater than 14. Usually pH scale is from 1-14, with 1 being very acidic and 14 being very basic. Since pH is greater than 14 this means that the solution is strongly basic.