The freezing point of an aqueous solution of KCN containing `0.1892" mole"//"kg" H_(2)O` was `-0.704^(@)C`. On adding 0.095 mole of `Hg(CN)_(2)`, the freezing point of solution was `-0.53^(@)C`. Assuming that complex is formed according to the reaction
`Hg(CN)_(2)+xCN^(-) to Hg(CN)_(x+2)^(x-)`
and also `Hg(CN)_(2)` is limiting reagent, find x.

Explanation

To solve the problem, we need to analyze the freezing point depression of the solution before and after the addition of Hg(CN)₂ and determine the value of x in the complex formation reaction.

### Step-by-Step Solution:

1. **Determine the initial freezing point depression (ΔTf) for KCN solution:**
- The initial freezing point of the KCN solution is -0.704°C.
- The freezing point of pure water is 0°C.
- Therefore, ΔTf = 0 - (-0.704) = 0.704°C.
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