Consider the following :

1. Pyroclastic debris

2. Ash and dust

3. Nitrogen compounds

4. Sulphur compounds

How many of the above are products of volcanic eruptions?

The correct answer is Option 4.

Key PointsVolcanic eruptions produce various materials, and among the listed items, the following are products of volcanic eruptions:

• Pyroclastic debris: These are fragments of rock erupted by a volcano, including pumice, ash, and volcanic bombs. Pyroclastic flows are fast-moving currents of hot gas and volcanic matter.
• Ash and dust: Volcanic ash and dust are fine particles of pulverized rock, minerals, and volcanic glass created during volcanic eruptions. These particles can be ejected into the atmosphere and carried over long distances.
• Sulphur compounds: Volcanic eruptions release various gases, including sulphur dioxide (SO₂) and hydrogen sulphide (H₂S). These sulphur compounds can have significant environmental and climatic effects.
• Nitrogen compounds: Volcanoes belched the gases that formed Earth's atmosphere. Those volcanoes could have also spurred lightning that fixed nitrogen, freeing it from nitrogen gas to form nitrogen-containing molecules that living things can use. 
• Hence, Option 4 is the correct answer.