25 g of an unknown hydrocarbon upon burning produces 88 g of CO2 and 9 g of H2O. This unknown hydrocarbon contains:
Some Basic Concepts (Mole Concept) · Class 11 · JEE Main Previous Year Question
25 g of an unknown hydrocarbon upon burning produces 88 g of and 9 g of . This unknown hydrocarbon contains:
- a
24 g of carbon and 1 g of hydrogen
- b
18 g of carbon and 7 g of hydrogen
- c
22 g of carbon and 3 g of hydrogen
- d✓
20 g of carbon and 5 g of hydrogen
20 g of carbon and 5 g of hydrogen
🧠 C from , H from Standard combustion analysis. Pull out the carbon mass from and the hydrogen mass from . The numbers should add to since the compound is only C and H.
🗺️ Step by step Mass of C . Mass of H .
Check: . The compound is fully accounted for.
So the answer is C and H.
⚠️ Common mistake Don't pick option (b) " C" — that comes from confusing the molar mass of water with the molar mass of carbon. Always use the ratio for carbon.
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