Statement I: pH of 10^-7 M - solution is in between 7.0 to 7.3 at 25°C.<br><br>Statement II: Due to — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

- Statement I is correct: At 25°C, for 10^-7 M $NaOH$, accounting for auto-ionization of water gives total [OH-] = 1.62 × 10^-7 M => pOH = 6.79 => pH = 7.21, which lies between 7.0 and 7.3.<br>- Statement II is correct: The addition of $NaOH$ (providing common ion OH-) shifts the water ionization equilibrium ($H_2O$ ⇌ H+ + OH-) to the left, suppressing water auto-ionization.<br>- However, Statement II is a qualitative statement and is not the quantitative explanation for the exact pH range. Thus, Statement II is not the correct explanation of Statement I.