`K_(a)` for `HA` is `4.9 xx 10^(-8)`. After making the necessary approximation, calculate for its decimolar solution,
a. `%` dissociation b. `overset(Θ)OH` concentration
c. `pH`

Explanation

To solve the problem step by step, we will calculate the percentage dissociation, hydroxide ion concentration, and pH of a decimolar solution of the weak acid HA with a given \( K_a \) value.

### Given:
- \( K_a = 4.9 \times 10^{-8} \)
- Concentration of HA, \( C = 0.1 \, \text{M} \)

### Step 1: Calculate the percentage dissociation (\( \alpha \))

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