Answer is: pH value of morphine is 10.64.
Chemical reaction: C₁₇H₁₉NO₃ + H₂O → C₁₇H₁₉NO₃H⁺ +OH⁻.
Kb(C₁₇H₁₉NO₃) = 10∧(-5,79) = 1,62·10⁻⁶.
c(C₁₇H₁₉NO₃) = 0,115 M.
Kb(C₁₇H₁₉NO₃) = c(OH⁻) · c(C₁₇H₁₉NO₃H⁺) ÷ c(C₁₇H₁₉NO₃).
c(OH⁻)
= c(C₁₇H₁₉NO₃H⁺) = x.
1,62·10⁻⁶ = x² ÷
(0,115 - x).
Solve quadratic equation: x = c(OH⁻) = 0,000431 M.
pOH = -log(0,000431 M) = 3,36.
pH = 14 - 3,36 = 10,64.
