Question

On complete combustion $0.30\, g$ of an organic compound gave $0.20 \,g$ of carbon dioxide and $0.10\, g$ of water. The percentage of carbon in the given organic compound is ________(Nearest Integer)

Answer 1

$\frac{ n _{ CO _{2}}}{ n _{ H _{2} O }}=\frac{ x }{ y / 2}=\frac{0.2 / 44}{.1 / 18}$
$\frac{2 x }{ y }=\frac{36}{44}=\frac{9}{11}$
$x =\frac{9 y }{22}$
$\frac{ n _{ C _{ x } H _{ y } O _{2}}}{ n _{ CO _{2}}}=\frac{1}{ x }$
$\frac{0.3}{12 x+y+16 z} \times \frac{44}{0.2}=\frac{1}{x}$
$66 x=12 x+y+16 z$
$54 x=y+16 z$
$\frac{54 \times 9 y}{22}-y=16 z$
$\frac{464 y}{22}=16 z$
$z =\frac{29 y }{22}$
$C _{ x } H _{ y } O _{ z }= C _{ x } H _{ y } O _{ z }$
$C _{\frac{9 y }{22}} H _{ y } O _{\frac{29 y }{}}^{22}$
$C _{9} H _{22} O _{29}$ $\%$ of $C =\frac{12 \times 9}{(12 \times 9+22+29 \times 16)} \times 100$
$=\frac{108}{594} \times 100$
$18.18 \%$