A solution of aniline (C₆H₅NH₂,K_b = 4.2 × 10^-10)has a pH of 8.56 at 25^oC.What was the initial concentration of aniline? A)2.8 × 10^-9 M B)2.1 × 10^-8 M C)3.2 × 10^-2 M D)4.2 × 10^-10 M E)3.6 × 10^-6 M

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Quizplus · Accepted Answer

The pH of 8.56 corresponds to a pOH of 5.44 (since pH + pOH = 14). The concentration of OH⁻ ions is 10^(-5.44) M. Using the Kb expression for aniline, [OH⁻]² = Kb × [C₆H₅NH₂], we can solve for the initial concentration of aniline, which is approximately 3.2 × 10⁻² M.

A Solution of Aniline (C6H5NH2,Kb = 4

A Solution of Aniline (C₆H₅NH₂,K_b = 4