Complete combustion of 1 . 80g of an oxygen containing compound ( C...

${n}_{{CO}_{2}} = \dfrac{2 . 64}{44} = 0 . 06$

${n}_{c} = 0 . 06$

weight of carbon $= 0 . 06 \times 12 = 0 . 72gm$

${n}_{{H}_{2}O} = \dfrac{1 . 08}{18} = 0 . 06$

${n}_{H} = 0 . 06 \times 2 = 0 . 12$

weight of $H = 0 . 12gm$

$= 1 . 8 - ( 0 . 72 + 0 . 12 )$

$= 0 . 96gram$

$$ weight of oxygen $= \dfrac{0 . 96}{1 . 8} \times 100$

The percentage of oxygen in the organic compound $= 53 . 3$.