${\mathrm{n}}_{{\mathrm{CO}}_2}=\frac{2.64}{44}=0.06$

${\mathrm{n}}_{\mathrm{c}}=0.06$

weight of carbon $=0.06\times 12=0.72 \mathrm{gm}$

${\mathrm{n}}_{{\mathrm{H}}_2\mathrm{O}}=\frac{1.08}{18}=0.06$

${\mathrm{n}}_{\mathrm{H}}=0.06\times 2=0.12$

 weight of $\mathrm{H}=0.12 \mathrm{gm}$

$= 1.8 - (0.72 + 0.12)$

$= 0.96 \mathrm{gram}$

 $\%$ weight of oxygen $=\frac{0.96}{1.8}\times 100$

The percentage of oxygen in the organic compound $= 53.3\%$.