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 ?
- (a) Only one
- (b) Only two
- (c) Only three
- (d) All four ✓ UPSC's answer
Why the answer is (d)
• A volcanic eruption ejects solid, liquid and gaseous products.
• Pyroclastic debris — fragments of rock, bombs, lapilli and pumice hurled from the vent — is a solid product (item 1).
• Ash and dust are the finest pyroclastic particles, which can travel thousands of kilometres and dim sunlight (item 2).
• Volcanic gases include water vapour, carbon dioxide, sulphur compounds (sulphur dioxide, hydrogen sulphide) that form aerosols and acid rain (item 4), and nitrogen and nitrogen compounds in smaller amounts (item 3).
• All four are eruption products, option (d).
Why the other options are wrong
- (a) Only one
- All four, not one, are volcanic products.
- (b) Only two
- Gases including nitrogen and sulphur compounds are also products.
- (c) Only three
- Nitrogen compounds are also emitted, making four.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2024, held on 16 June 2024. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.