When excess sodium thiosulphate is added to AgBr, the product formed is

Options

A. `Ag_2S_2O_3`
B. `Na[Ag(S_2,O_3)]`
C. `Na_3[AgBr_4]`
D. `Na_3[Ag(S_2O_3)_2]`

Answer

To solve the question of what product is formed when excess sodium thiosulfate is added to AgBr, we can follow these steps:

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

### Step 2: Understand the Reaction
Sodium thiosulfate is known to form complexes with silver ions. When it is added to AgBr, it reacts with the silver ions (Ag+) present in AgBr.

### Step 3: Write the Reaction Equation
The reaction can be represented as follows:
\[ \text{AgBr} + \text{Na}_2\text{S}_2\text{O}_3 \rightarrow \text{Na}_3\text{AgS}_2\text{O}_3 + \text{NaBr} \]

### Step 4: Balance the Reaction
To ensure that the reaction is balanced, we need to ensure that the number of atoms of each element is the same on both sides of the equation. The balanced equation is:
\[ 3\text{Na}_2\text{S}_2\text{O}_3 + 2\text{AgBr} \rightarrow 2\text{Na}_3\text{AgS}_2\text{O}_3 + 2\text{NaBr} \]

### Step 5: Identify the Product
From the balanced equation, we can see that the product formed when excess sodium thiosulfate is added to AgBr is:
\[ \text{Na}_3\text{AgS}_2\text{O}_3 \]

### Conclusion
Thus, the product formed when excess sodium thiosulfate is added to AgBr is:
**Na3AgS2O3 (silver thiosulfate complex)**.