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10 mL of gaseous hydrocarbon on combustion gives 40 mL of CO2(g) and 50 mL of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is .
14
CxHy + (x + y4 )O2 xCO2 + y2H2O
∵ at the same T and P, volume ratio = mole ratio:
10x = 40 ⇒ x = 4
10 × y2 = 50 ⇒ y = 10
⇒ hydrocarbon = C4H10 ∴ C + H atoms = 4 + 10 = 14
Answer: 14
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