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Topic Laws of chemical combination
Asked 2 times across 2 UPSC exams over 4 years (2022–2026), peaking in 2026.
Key insights
- Most tested in NDA — 1 of 2 PYQs
- Most asked in 2026
- Recurs across 2 years (2022–2026)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
GEO 2022 → NDA 2026
How the concept evolved
Rising — more than half its appearances (2 of 2) 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.
NDA2026
1·7 g of silver nitrate is dissolved in 100 g of water, and 0·585 g of sodium chloride is dissolved in 100 g of water. Both are mixed and a chemical reaction occurs. 1·435 g of silver chloride and 0·85 g of sodium nitrate are formed. Which law of chemical combination is shown by the above reaction?
- A Law of multiple proportions
- B Law of conservation of mass ✓
- C Law of reciprocal proportions
- D Law of constant proportions
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
GEO2022
Which one of the following statements about the law of chemical combination is not correct?
- A Equal volumes of all gases at the same temperature and pressure contain equal number of molecules.
- B If two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of other element, are not in a simple proportion. ✓
- C Matter can neither be created nor destroyed.
- D A given compound always contains exactly the same proportion of elements by weight.
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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