Soham, a class 9 student mixed some iron filings and sulphur in a China dish and heated them strongly to obtain a residue. Which of the following is not a characteristic property of the residue?

Options

A. It cannot be separated into sulphur and iron filings by normal physical methods.
B. Its properties are completely different from iron and sulphur.
C. Its composition is same throughout.
D. Its appearance is different from iron and sulphur but it shows chemical properties of both iron and sulphur.

Explanation

To solve the question regarding the characteristics of the residue obtained from heating a mixture of iron filings and sulfur, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Mixture**:
- Soham mixed iron filings (Fe) and sulfur (S) in a china dish. When these two elements are mixed, they do not react immediately at room temperature.

2. **Heating the Mixture**:
- Upon heating the mixture strongly, a chemical reaction occurs between iron and sulfur, forming iron sulfide (FeS), which is the residue left after heating.

3. **Identifying Properties of the Residue**:
- The properties of the residue (iron sulfide) differ from those of the individual components (iron and sulfur).
- Iron sulfide is a compound with its own distinct properties, which include:
- It is a solid at room temperature.
- It has a different color (usually grayish-black) compared to the original iron filings (which are gray) and sulfur (which is yellow).
- It is not attracted to a magnet, unlike iron filings.

4. **Evaluating the Given Statements**:
- The question asks which of the following is NOT a characteristic property of the residue.
- We need to analyze the statements provided (not included in the question) to determine which statement does not accurately describe the properties of iron sulfide.

5. **Conclusion**:
- The statement that suggests the residue shows the chemical properties of both iron and sulfur is incorrect. Iron sulfide does not exhibit the properties of the individual elements but rather has its own distinct properties.

### Final Answer:
The statement that is NOT a characteristic property of the residue is: "The residue shows chemical properties of both iron and sulfur."

---