Sodium thiosulphate can be prepared by

Options

A. Boiling `Na_(2)SO_(3)` solution with sulphur in acidic medium
B. Boling an aqueous solution of NaOH with sulphur
C. Neutralising `H_(2)SO_(4)` with NaOH
D. Boiling `Na_(2)SO_(3)` with sulphur in alkaline medium

Explanation

To prepare sodium thiosulfate (Na2S2O3), we can follow a specific reaction pathway. Here’s a step-by-step solution to the preparation of sodium thiosulfate:

### Step 1: Identify the Reactants
We need to prepare sodium thiosulfate from sodium sulfite (Na2SO3) and sulfur (S) in the presence of an acidic or alkaline medium.

### Step 2: Choose the Medium
The preparation can be done in either acidic or alkaline medium. However, sodium thiosulfate is more stable in an alkaline medium.

### Step 3: Reaction in Alkaline Medium
In an alkaline medium, the reaction can be represented as follows:
\[ \text{Na}_2\text{SO}_3 + \text{S} + \text{OH}^- \rightarrow \text{Na}_2\text{S}_2\text{O}_3 + \text{H}_2\text{O} \]

### Step 4: Write the Balanced Equation
The balanced equation for the reaction in alkaline medium is:
\[ \text{2 Na}_2\text{SO}_3 + \text{S} \rightarrow \text{2 Na}_2\text{S}_2\text{O}_3 + \text{H}_2\text{O} \]

### Step 5: Conclusion
Thus, sodium thiosulfate can be prepared by boiling sodium sulfite with sulfur in an alkaline medium.

### Summary
- Sodium thiosulfate is prepared from sodium sulfite and sulfur.
- The reaction is performed in an alkaline medium to ensure stability and yield of sodium thiosulfate.