Detailed Explanation:

Answer: Option 4 — All four

All four items listed—pyroclastic debris, ash and dust, nitrogen compounds, and sulphur compounds—are products of volcanic eruptions. Volcanic eruptions release both solid materials (pyroclastic debris, ash) and various gases (nitrogen and sulphur compounds) that can have significant environmental impacts.

✅ Statement 1 – Correct: Pyroclastic debris includes fragmental materials like ash, pumice, cinders, and volcanic bombs ejected during eruptions.
✅ Statement 2 – Correct: Ash and dust are fine-grained particles of volcanic rock and glass produced during explosive volcanic activity.
✅ Statement 3 – Correct: Nitrogen compounds such as ammonia (NH₃) and nitrogen oxides (NOₓ) are released from volcanic gases.
✅ Statement 4 – Correct: Sulphur compounds, particularly sulphur dioxide (SO₂) and hydrogen sulphide (H₂S), are major volcanic gases.

📝 Short Notes: Products of Volcanic Eruptions

• Environmental Impact: Volcanic ash can disrupt air travel, damage crops, and contaminate water supplies; sulphur dioxide contributes to acid rain and can affect global climate by forming aerosols in the stratosphere.
• Tephra: General term for all pyroclastic material ejected during an eruption, regardless of size or composition.
• Volcanic Winter: Large eruptions releasing significant ash and SO₂ can block sunlight, temporarily cooling the Earth's surface.
• Health Hazards: Fine volcanic ash can cause respiratory problems; gases like SO₂ and H₂S are toxic in high concentrations.