Which of the following statements is`//`are correct?

Options

A. `PbO_(2)` reacts with `HCl` to evolve `Cl_(2)` gas.
B. `PbO_(2)` reacts with `HNO_(3)` to form `O_(2)` gas.
C. `Pb_(3)O_(4)` reacts with `HCl` to evolve `Cl_(2)` gas.
D. `Pb_(3)O_(4)` reacts with `HNO_(3)` to form `PbO_(2)`, but `O_(2)` is not liberated.

Explanation

To determine which statements are correct regarding the reactions of lead oxides with acids, we will analyze each statement step by step.

### Step 1: Analyze Statement 1
**Statement:** PbO2 reacts with HCl to evolve chlorine gas.

**Analysis:**
- When lead dioxide (PbO2) reacts with hydrochloric acid (HCl), it does not produce chlorine gas (Cl2). Instead, the reaction produces lead(II) chloride (PbCl2) and hydrogen gas (H2).
- The balanced equation for this reaction is:
\[ PbO2 + 4HCl \rightarrow PbCl2 + 2H2O + Cl2 \]
- However, the primary products are PbCl2 and H2, not Cl2 in significant amounts.

**Conclusion:** This statement is **incorrect**.

### Step 2: Analyze Statement 2
**Statement:** PbO2 reacts with nitric acid (HNO3) to evolve oxygen gas.

**Analysis:**
- When lead dioxide (PbO2) reacts with concentrated nitric acid, it produces lead(II) nitrate (Pb(NO3)2), oxygen gas (O2), and water (H2O).
- The balanced equation for this reaction is:
\[ PbO2 + 4HNO3 \rightarrow Pb(NO3)2 + 2H2O + O2 \]
- This confirms that oxygen gas is indeed evolved.

**Conclusion:** This statement is **correct**.

### Step 3: Analyze Statement 3
**Statement:** Pb3O4 reacts with HCl to evolve chlorine gas.

**Analysis:**
- When lead(II,IV) oxide (Pb3O4) reacts with hydrochloric acid (HCl), it produces lead(II) chloride (PbCl2) and lead dioxide (PbO2), along with water.
- The balanced equation for this reaction is:
\[ Pb3O4 + 8HCl \rightarrow 3PbCl2 + 2PbO2 + 4H2O \]
- Chlorine gas is not evolved in this reaction.

**Conclusion:** This statement is **incorrect**.

### Step 4: Analyze Statement 4
**Statement:** Pb3O4 reacts with nitric acid (HNO3) to form PbO2.

**Analysis:**
- When Pb3O4 reacts with nitric acid, it produces lead dioxide (PbO2), lead(II) nitrate (Pb(NO3)2), and water.
- The balanced equation for this reaction can be represented as:
\[ Pb3O4 + 8HNO3 \rightarrow 3Pb(NO3)2 + 2PbO2 + 4H2O \]
- This confirms that PbO2 is indeed formed.

**Conclusion:** This statement is **correct**.

### Final Conclusion
The correct statements are:
- Statement 2: PbO2 reacts with nitric acid to evolve oxygen gas (Correct).
- Statement 4: Pb3O4 reacts with nitric acid to form PbO2 (Correct).