Colloidal sulphur is obtained when

Options

A. sulphur is heated gradually to high temperature
B. sulphur is heated with dilute sulphuric acid
C. hydrogen sulphide is passed through an aqueous solution of nitric acid
D. sulphur is warned with carbon disulphide

Answer

To determine how colloidal sulfur is obtained, we can break down the process into clear steps:

### Step 1: Understanding the Reactants
Colloidal sulfur is formed through a chemical reaction involving hydrogen sulfide (H₂S) and nitric acid (HNO₃).

### Step 2: Decomposition of Nitric Acid
When nitric acid (HNO₃) is decomposed, it produces nitrogen dioxide (NO₂), water (H₂O), and nascent oxygen (O). The reaction can be represented as:
\[ 4HNO_3 \rightarrow 4NO_2 + 2H_2O + O \]

### Step 3: Reaction of Nascent Oxygen with Hydrogen Sulfide
The nascent oxygen produced in the previous step reacts with hydrogen sulfide (H₂S) to form sulfur (S) and water (H₂O). This reaction can be represented as:
\[ 2H_2S + O \rightarrow 2S + 2H_2O \]

### Step 4: Formation of Colloidal Sulfur
The sulfur produced from the above reaction is in a colloidal form, which means it is dispersed in a medium (usually water) but not dissolved.

### Conclusion
Thus, colloidal sulfur is obtained when hydrogen sulfide is passed through an aqueous solution of nitric acid.

### Final Answer
Colloidal sulfur is obtained when hydrogen sulfide is passed through an aqueous solution of nitric acid.

---