Very dilute solution of sodium thiosulphate reacts with a solution of silver nitrate finally to give

Options

A. White `Ag_(2)S_(2)O_(3)` precipitate
B. Black `Ag_(2)S_(2)O_(3)` precipitate
C. White `Ag_(2)S` precipitate
D. Black `Ag_(2)S` precipitate

Answer

To solve the question regarding the reaction between a very dilute solution of sodium thiosulfate and silver nitrate, we will follow these steps:

### Step 1: Write the chemical formulas
Identify the chemical formulas of the reactants involved in the reaction.
- Sodium thiosulfate is represented as Na₂S₂O₃.
- Silver nitrate is represented as AgNO₃.

### Step 2: Write the balanced chemical equation
When sodium thiosulfate reacts with silver nitrate, the products formed are silver thiosulfate and sodium nitrate. The balanced chemical equation for this reaction can be written as:
\[ \text{Na}_2\text{S}_2\text{O}_3 + 2 \text{AgNO}_3 \rightarrow \text{Ag}_2\text{S}_2\text{O}_3 + 2 \text{NaNO}_3 \]

### Step 3: Consider the dilution effect
Since the solution is very dilute, the silver thiosulfate (Ag₂S₂O₃) formed may further decompose or react to form silver sulfide (Ag₂S), which is a black precipitate. This can be represented as:
\[ \text{Ag}_2\text{S}_2\text{O}_3 \rightarrow \text{Ag}_2\text{S} + \text{SO}_2 + \text{O}_2 \]

### Step 4: Identify the final product
The final product of the reaction, considering the dilution and the formation of precipitate, is silver sulfide (Ag₂S), which is known for its black color.

### Conclusion
Thus, the final product of the reaction between very dilute sodium thiosulfate and silver nitrate is black silver sulfide (Ag₂S).

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