On treating sodium fusion extract with sodium nitroprusside, a violet colour was observed. This indicates the presence of which element in the organic compound?

Options

A. Nitrogen
B. Sulphur
C. Chlorine
D. Bromine

Answer

To determine the element present in the organic compound based on the observation of a violet color when treating a sodium fusion extract with sodium nitroprusside, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Reaction Context**:
- Sodium fusion extract is a solution obtained by fusing an organic compound with sodium metal, which helps in detecting certain elements present in the compound.

2. **Identify the Reagent**:
- Sodium nitroprusside (Na2[Fe(CN)5NO]) is used in this test. It is known to react with certain elements to produce a color change.

3. **Observe the Color Change**:
- The question states that a violet color is observed upon adding sodium nitroprusside to the sodium fusion extract.

4. **Determine the Element Indicated by the Color Change**:
- The appearance of a violet color specifically indicates the presence of sulfur (S) in the organic compound. This is a characteristic reaction where sodium nitroprusside forms a complex with sulfide ions, resulting in a violet color.

5. **Confirm the Element**:
- Based on the known reactions, we can conclude that the violet color confirms the presence of sulfur in the organic compound.

### Final Answer:
The element indicated by the violet color observed when treating the sodium fusion extract with sodium nitroprusside is **sulfur**.