If the equilibrium constant for the reaction of weak acid HA with strong base is `10^(9)`, then pH of `0.1M` Na A is:

Explanation

To solve the problem, we need to determine the pH of a 0.1 M solution of sodium salt of a weak acid (NaA) given that the equilibrium constant for the reaction of the weak acid (HA) with a strong base (NaOH) is \(10^9\).

### Step-by-Step Solution:

1. **Identify the Reaction**:
The weak acid (HA) reacts with a strong base (NaOH) to form its salt (NaA) and water:
\[
HA + OH^- \rightleftharpoons A^- + H_2O
...