The pH of solution is (For , , , ) — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

Hydrazine is a dibasic weak base, but $[\text{OH}^-]$ is determined by $K_{b1}$ since $K_{b1} \gg K_{b2}$. $[\text{OH}^-] \approx \sqrt{K_{b1} C} = \sqrt{3.6 \times 10^{-6} \times 0.1} = \sqrt{36 \times 10^{-8}} = 6.0 \times 10^{-4}\text{ M}$. $\text{pOH} = -\log(6.0 \times 10^{-4}) = 4 - \log 6 = 4 - (\log 2 + \log 3) = 4 - (0.3 + 0.48) = 4 - 0.78 = 3.22$. The $\text{pH} = 14 - \text{pOH} = 14 - 3.22 = 10.78$.