Topic Gases
Asked 3 times across 2 UPSC exams over 7 years (2018–2025), peaking in 2022.
Key insights
- Most tested in CDS — 2 of 3 PYQs
- Most asked in 2022
- Recurs across 3 years (2018–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CDS 2018 → CAPF 2022
How the concept evolved
Rising — more than half its appearances (3 of 3) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
CDS2025
Which one of the following gas is used in making soft drinks ?
- A NH₃
- B PH₃
- C COCl₂
- D CO₂ ✓
✓ Correct answer: (D)
Science & Technology › Physics & Chemistry
CAPF2022
Which of the following makes bread soft and spongy when baking soda is added?
- A Sodium salt of acid
- B NaHCO3
- C CO2 ✓
- D H2O
✓ Correct answer: (C)
Science & Technology › Physics & Chemistry
CDS2018
Which of the following characteristics is common to hydrogen, nitrogen, oxygen and carbon dioxide?
- A They are all diatomic.
- B They are all gases at room temperature. ✓
- C They are all coloured.
- D They all have same reactivity.
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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