Horn silver ore dissolves in excess of sodium cyanide solution forming

Options

A. AgCN
B. `Na[Ag(CN)_(2)]`
C. `Na_(2)[Ag(CN)_(2)]`
D. `Na_(4)[Ag(CN)_(5)]`

Explanation

To solve the question regarding the dissolution of horn silver ore in excess sodium cyanide solution, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Horn Silver Ore**:
Horn silver ore is also known as chlorargyrite, which is primarily composed of silver chloride (AgCl).

2. **Reaction with Sodium Cyanide**:
When horn silver (AgCl) is treated with sodium cyanide (NaCN), a complex formation occurs. The sodium cyanide acts as a ligand that binds to the silver ion.

3. **Formation of Silver Cyanide Complex**:
The reaction can be represented as:
\[ \text{AgCl} + 2 \text{NaCN} \rightarrow \text{Na}_2\text{Ag(CN)}_2 + \text{NaCl} \]
In this reaction, silver chloride reacts with sodium cyanide to form sodium dicyanoargentate(I) (Na₂Ag(CN)₂) and sodium chloride (NaCl).

4. **Complex Stability**:
The resulting complex, Na₂Ag(CN)₂, is water-soluble. In this complex, silver is in the +1 oxidation state (Ag⁺), which is more stable than the +2 oxidation state (Ag²⁺) due to its electronic configuration.

5. **Conclusion**:
Therefore, when horn silver ore dissolves in excess sodium cyanide solution, it forms the complex Na₂Ag(CN)₂.

### Final Answer:
Horn silver ore dissolves in excess sodium cyanide solution forming **Na₂Ag(CN)₂**.