Question

The complete combustion of 0.492 g of an organic compound containing 'C', 'H' and 'O' gives 0.793 g of CO2 and 0.442 g of H2O. The percentage of oxygen composition in the organic compound is_____.[nearest integer]

Answer 1

The correct answer is 46
CxHyOz + O2 → CO2 + H2O
Weight ~of ~carbon $=\frac{0.793}{44}×12=0.216 g$
Weight of hydrogen $=\frac{0.442}{18}×2=0.05 g$
weight of oxygen = 0.492 – (0.216 + 0.05)
= 0.226 g
Percentage by mass of oxygen in compound :
$=\frac{0.226}{0.492}×100≃46$%