In a study of aqueous solution of thorium nitrate, the freezing point depression of `0.0703^(@)C` is observed for a `9.6 mmol kg^(-1)` of the solution. How many ions are present in one thorium nitrate unit? "(`K_(f)` for` H_(2)O=1.86 K m^(-1)`)"

Explanation

To solve the problem, we need to determine how many ions are present in one unit of thorium nitrate (Th(NO3)4) based on the given freezing point depression and molality of the solution.

### Step-by-Step Solution:

1. **Identify the formula for freezing point depression**:
The freezing point depression (\( \Delta T_f \)) is given by the formula:
\[
\Delta T_f = i \cdot K_f \cdot m
...