Question

$0.46 \,g$ of an organic compound was analysed. The increase in mass of $CaCl_{2}$ $U$-tube was $0.54 \,g$ and potash bulb was $0.88 \,g$. The percentage composition of the compound is

• A. $C = 52.17\%, H = 13.04 \%, O = 34.79\%$
• B. $C = 50\%, H = 50\%$
• C. $C=32.19\%, H = 18.01\%, O = 49.8\%$
• D. $C = 72\%, H = 28 \%$

Answer 1

Answer: (A)

Mass of $H_{2}O = 0.54 \,g$
Mass of $CO_{2} = 0.88 \,g$
$\%$ of $C=\frac{12}{44}\times\frac{0.88}{0.46}\times100=52.17\%$
$\%$ of $H =\frac{2}{18}\times\frac{0.54}{0.46}\times100=13.04\%$
$\%$ of $O=100-\left(52.17+13.04\right)=34.79\%$