What happens when silver nitrate solution is added to `Na_(2)S_(2)O_(3)` solution and then content is allowed to keep for a longer period?

Answer

To solve the question regarding the reaction between silver nitrate solution (AgNO3) and sodium thiosulfate solution (Na2S2O3), let's break it down step by step:

### Step 1: Identify the Reactants
The reactants in this scenario are:
- Silver nitrate (AgNO3)
- Sodium thiosulfate (Na2S2O3)

### Step 2: Write the Reaction
When silver nitrate is added to sodium thiosulfate, a double displacement reaction occurs. The products of this reaction are:
- Silver thiosulfate (Ag2S2O3)
- Sodium nitrate (NaNO3)

The balanced chemical equation for this reaction is:
\[ 2 \text{AgNO}_3 + \text{Na}_2\text{S}_2\text{O}_3 \rightarrow \text{Ag}_2\text{S}_2\text{O}_3 + 2 \text{NaNO}_3 \]

### Step 3: Observe the Precipitate
Upon mixing the solutions, a white precipitate of silver thiosulfate (Ag2S2O3) is formed.

### Step 4: Allow the Mixture to Stand
If the mixture is allowed to stand for a longer period, the white precipitate will undergo changes in color:
- Initially, it is white.
- After some time, it turns yellow.
- Eventually, it turns brown.

### Step 5: Reaction with Water
If the brown precipitate is further treated with water, it decomposes to form:
- Silver sulfide (Ag2S), which is a black solid.
- Sulfuric acid (H2SO4) is also released as a byproduct.

### Final Summary of Changes
1. **Initial Reaction**: Formation of white precipitate (Ag2S2O3).
2. **Color Change**: White → Yellow → Brown upon standing.
3. **Decomposition**: Brown precipitate reacts with water to form black Ag2S and H2SO4.