Read the Assertion and Reason below and choose the correct option. — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The total $[\text{OH}^-]$ in $10^{-7}\text{ M NaOH}$ is the sum of $\text{OH}^-$ from the base and from water's autoionization. While water's ionization is suppressed by the common ion effect (Statement II is true), the total $[\text{OH}^-]$ evaluates to $\approx 1.618 \times 10^{-7}\text{ M}$, yielding a pH of $\approx 7.21$, which is between 7.0 and 7.3 (Statement I is true). However, Statement II is not the strict mathematical explanation for the pH range, which stems from the additive contribution of both sources.