Which of the following combination of species can evolve `O_(2)`?

Options

A. `PbO_(2)+`warm conc. `H_(2)SO_(4)`
B. `NaOH+F_(2)`
C. `PbO_(2)+`conc. `HNO_(3)`
D. `XeF_(2)+H_(2)O`

Explanation

To determine which combinations of species can evolve oxygen gas (O₂), we will analyze each reaction provided in the question step by step.

### Step 1: Analyze the first reaction
**Reaction:** PbO + warm concentrated H₂SO₄

- **Reactants:** Lead oxide (PbO) and warm concentrated sulfuric acid (H₂SO₄).
- **Products:** Lead sulfate (PbSO₄), oxygen gas (O₂), and water (H₂O).

**Conclusion:** This reaction evolves oxygen gas.

### Step 2: Analyze the second reaction
**Reaction:** NaOH + Cl₂

- **Reactants:** Sodium hydroxide (NaOH) and chlorine gas (Cl₂).
- **Products:** Sodium chloride (NaCl), oxygen gas (O₂), and water (H₂O).

**Conclusion:** This reaction also evolves oxygen gas.

### Step 3: Analyze the third reaction
**Reaction:** PbO + concentrated HNO₃

- **Reactants:** Lead oxide (PbO) and concentrated nitric acid (HNO₃).
- **Products:** Lead nitrate (Pb(NO₃)₂), oxygen gas (O₂), and water (H₂O).

**Conclusion:** This reaction evolves oxygen gas as well.

### Step 4: Analyze the fourth reaction
**Reaction:** XeF₆ + H₂O

- **Reactants:** Xenon hexafluoride (XeF₆) and water (H₂O).
- **Products:** Xenon (Xe), oxygen gas (O₂), and hydrogen fluoride (HF).

**Conclusion:** This reaction also produces oxygen gas.

### Final Conclusion
After analyzing all the reactions, we find that all the provided combinations of species can evolve oxygen gas (O₂). Therefore, the answer to the question is that all options are correct.

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