`underset(("Black"))(X)overset(Dil.H_(2)SO_(4))tounderset(("gas"))(Y)overset(Dil.HNO_(3))to` Colloidal sulphur identify X?

Options

A. CuS
B. FeS
C. PbS
D. NiS

Explanation

To identify the compound X in the given sequence of reactions, we can follow these steps:

### Step 1: Analyze the properties of compound X
- The problem states that compound X is black in color. A common black compound in inorganic chemistry is ferrous sulfide (FeS).

**Hint:** Look for black-colored inorganic compounds that can react with dilute sulfuric acid.

### Step 2: Reaction of X with dilute H2SO4
- When ferrous sulfide (FeS) reacts with dilute sulfuric acid (H2SO4), it produces hydrogen sulfide gas (H2S) and ferrous sulfate (FeSO4).

\[ \text{FeS} + \text{H}_2\text{SO}_4 \rightarrow \text{H}_2\text{S} + \text{FeSO}_4 \]

**Hint:** Remember that the reaction of sulfides with acids typically produces hydrogen sulfide gas.

### Step 3: Identify gas Y
- The gas produced in this reaction is hydrogen sulfide (H2S), which is a colorless gas with a characteristic smell.

**Hint:** Identify the gas produced in the reaction of sulfides with acids.

### Step 4: Reaction of gas Y with dilute HNO3
- The next step involves the reaction of hydrogen sulfide (H2S) with dilute nitric acid (HNO3). This reaction leads to the formation of colloidal sulfur (S), nitrogen dioxide (NO2), and water (H2O).

\[ 6 \text{H}_2\text{S} + 6 \text{HNO}_3 \rightarrow 3 \text{S} + 6 \text{NO}_2 + 6 \text{H}_2\text{O} \]

**Hint:** Consider the products formed when hydrogen sulfide reacts with nitric acid.

### Step 5: Conclusion
- From the above reactions, we conclude that compound X is ferrous sulfide (FeS), and the gas Y produced is hydrogen sulfide (H2S). The final product is colloidal sulfur.

**Final Answer:** Compound X is ferrous sulfide (FeS).