`Cd(CN)_(2)darr+2KCN to K_(2)[Cd(CN)_(4)]`

Options

A. For precipitate formation reaction
B. For precipitate dissolution reaction
C. For precipitate exchange reaction
D. For no reaction

Answer

To determine the type of reaction represented by the equation:

\[ \text{Cd(CN)}_2 + 2 \text{KCN} \rightarrow \text{K}_2[\text{Cd(CN)}_4] \]

we will analyze the components of the reaction step by step.

### Step 1: Identify the Reactants
The reactants in this reaction are:
- Cadmium cyanide, \(\text{Cd(CN)}_2\)
- Potassium cyanide, \(\text{KCN}\)

### Step 2: Identify the Products
The product of the reaction is:
- Potassium tetra-cyanocadmate, \(\text{K}_2[\text{Cd(CN)}_4]\)

### Step 3: Analyze the Reactants and Products
In the reactants, \(\text{Cd(CN)}_2\) is a precipitate, as indicated by the downward arrow in the original equation. This suggests that it is not soluble in the reaction medium.

### Step 4: Determine the Nature of the Reaction
When \(\text{Cd(CN)}_2\) reacts with \(\text{KCN}\), it forms a soluble complex, \(\text{K}_2[\text{Cd(CN)}_4]\). The formation of this soluble complex indicates that the precipitate (\(\text{Cd(CN)}_2\)) is dissolving in the presence of \(\text{KCN}\).

### Step 5: Classify the Reaction
Since a precipitate is dissolving to form a soluble complex, this reaction is classified as a **precipitate dissolution reaction**.

### Conclusion
The type of reaction is a **precipitate dissolution reaction**.

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