Sulphan' is

Options

A. A mixture of `SO_(3)` and `H_(2)SO_(5)`
B. 100 % conc. `H_(2)SO_(4)`
C. A mixture of gypsum and conc. `H_(2)SO_(4)`
D. 100 % oleum (a mixture of 100 % `SO_(3)` in 100 % `H_(2)SO_(4)`)

Explanation

To solve the question regarding "Sulphan," we need to clarify the context and the components involved. Based on the information provided in the video transcript, it seems that "Sulphan" refers to oleum, which is a solution of sulfur trioxide (SO3) in sulfuric acid (H2SO4).

### Step-by-Step Solution:

1. **Understanding Sulfan**:
- The term "Sulphan" is likely a misspelling or misinterpretation of "oleum," which is a chemical compound consisting of sulfur trioxide (SO3) dissolved in sulfuric acid (H2SO4).

2. **Components of Oleum**:
- Oleum can be represented as H2SO4 + SO3. This means that it is formed by adding sulfur trioxide to sulfuric acid.

3. **Concentration of Oleum**:
- Oleum can be concentrated, and the term "100% oleum" refers to a solution where SO3 is fully dissolved in H2SO4 without any excess water.

4. **Chemical Representation**:
- The chemical formula for oleum can be expressed as H2S2O7, which is the result of the combination of H2SO4 and SO3.

5. **Final Conclusion**:
- Therefore, "Sulphan" is essentially oleum, which is a mixture of sulfur trioxide and sulfuric acid.