Question

$0.45$ g of an organic compound containing only $C,H$ and $N$ on combustion gave $1.1$ g of $C{O}_2$ and $0.3$ g of $H_{2}O$. What is the percentage of $C,H$ and $N$ in the organic compound?

• A. $C=66.6$%6, $H=7.4$% , $N=25.93$%
• B. $C=56.6$%6, $H=12.4$% , $N=30.93$%
• C. $C=76.6$%6, $H=7.4$% , $N=15.93$%
• D. None of these

Answer 1

The correct option is A $C=66.6$%6, $H=7.4$% , $N=25.93$%

% of $C=\frac{12}{44}\times \frac{\text{Weight of}C{O}_2\times 100}{\text{Weight of compound}}$ $=\frac{12\times 1.1\times 100}{44\times 0.45}=66.66$%
% of $H=\frac{2}{18}\times \frac{\text{Weight of}{H}_{2}O\times 100}{\text{Weight of compound}}$ $=\frac{2\times 0.3\times 100}{18\times 0.45}=7.4$%
% of $N=[100-(66.66+7.4\left)\right]=25.93$%