Iron (II)sulphide gives foul smell of (a)___.

Answer

To solve the question "Iron (II) sulfide gives foul smell of (a)___", we can follow these steps:

### Step 1: Identify the compound
Iron (II) sulfide is represented by the chemical formula FeS.

### Step 2: Understand the reaction with moisture
When Iron (II) sulfide (FeS) comes into contact with moisture (water), it undergoes a chemical reaction.

### Step 3: Write the reaction
The reaction can be summarized as follows:
\[ \text{FeS} + \text{H}_2\text{O} \rightarrow \text{FeO} + \text{H}_2\text{S} \]
In this reaction, Iron (II) sulfide reacts with water to form Iron (II) oxide (FeO) and Hydrogen sulfide (H₂S).

### Step 4: Identify the foul smell
Hydrogen sulfide (H₂S) is known for its characteristic foul smell, often described as that of rotten eggs.

### Step 5: Fill in the blank
Thus, the answer to the question is that Iron (II) sulfide gives a foul smell of **Hydrogen sulfide (H₂S)**.

### Final Answer:
Iron (II) sulfide gives foul smell of **Hydrogen sulfide (H₂S)**.

---