Which of the following is equivalent to the complex number i^28

pH before addition of KOH = 4.03

pH after addition of 25 ml KOH = 7.40

pH after addition of 30 ml KOH = 7.57

pH after addition of 40 ml KOH = 8.00

pH after addition of 50 ml KOH = 10.22

pH after addition 0f 60 ml KOH = 12.3

Explanation:

pH of each case in the titration given below

(6) After addition of 60 ml KOH

Since addition of 10 ml extra KOH is added after netralisation point.

Concentration of solution after addition 60 ml KOH is calculated by

M₁V₁ = M₂V₂

or, 0.23 x 10 = (50 + 60)ml x M₂

or M₂ = 0.03 Molar

so, concentration of KOH = 0.03 molar

                               [OH⁻] = 0.03 molar

                                 pOH = 0.657

                                  pH = 14 - 0.657 = 13.34