Question

Complete combustion of $1.80 g$ of an oxygen containing compound $\left( C _{ x } H _{ y } O _{2}\right)$ gave $2.64 g$ of $CO _{2}$ and $1.08 g$ of $H _{2} O$. The percentage of oxygen in the organic compound is:

• A. 51.63
• B. 63.53
• C. 53.33
• D. 50.33

Answer 1

Answer: (C)

$n _{ c }= n _{ co _{2}}=\frac{2.64}{44}=0.06$

$n _{ H }=2 \times n _{ H _{2} O }=\frac{1.08}{18} \times 2=0.12$

$m _{0}=1.80-12 \times \frac{2.64}{44}-\frac{1.08}{18} \times 2$

$\quad=1.80-0.72-0.12=0.96 gm$

$\% 0=\frac{0.96}{1.80} \times 100=53.33 \%$