AIIMS 2019 Chemistry Salt hydrolysis MCQ Question

The calculation of pH using the formula $\text{pH} = \frac{1}{2} (\text{p}K_a + \text{p}K_b + \text{p}K_w)$ is valid for a salt formed from a weak acid and a weak base, where $\text{p}K_w$ is the ion product of water (14 at 25°C). In this case, substituting the values $\text{p}K_a = 4$, $\text{p}K_b = 5$, and $\text{p}K_w = 14$ yields a pH of 6.5, indicating a neutral solution. Since all other options are marked as N/A, they do not provide relevant alternatives or correct answers.