Question

The complete combustion of $0.492\, g$ of an organic compound containing ' $C$ ', ' $H$ ' and ' $O$ ' gives $0.793\, g$ of $CO _{2}$ and $0.442\, g$ of $H _{2} O$. The percentage of oxygen composition in the organic compound is __(nearest integer)

Answer 1

Mole of $CO _{2}=$ Moles of $C =\frac{0.793}{44}$
Weight of ' $C$ ' $=\frac{0.793}{44} \times 12=0.216 \,gm$
Moles of ' $H ^{\prime}=\frac{0.442}{18} \times 2$
Weight of ' $H ^{\prime}=\frac{0.442}{18} \times 2 \times 1=0.04\,9 gm$
$\therefore$ Weight of ' $O$ ' $=0.492-0.216-0.049=0.227\, gm$
$\%$ of ' ${ }^{\prime}{ }^{\prime}=\frac{0.227}{0.492} \times 100=46.13 \%$