Question

On complete combustion, $0.246\, g$ of an organic compound gave $0.198\, g$ of carbon dioxide and $0.1014\, g$ of water. The percentage composition of carbon and hydrogen in the compound respectively are

• A. $\% C - 21.95 , \% H - 4.58$
• B. $\% C - 21.95, \% H -5.58$
• C. $\% C - 11.95, \% H -5.58$
• D. $\% C - 11.95, \% H -4.58$

Answer 1

Answer: (A)

Given mass of $CO _{2}=0.198\, g$ and mass of $H _{2} O =0.1014\, g$
As we know, $\%$ of $C =\frac{12}{44} \times \frac{m_{ CO _{2}}}{w} \times 100$
Percentage of carbon $=\frac{12 \times 0.198 \times 100}{44 \times 0.246}=21.95 \%$
Also,$H =\frac{2}{18} \times \frac{m_{ H _{2} O }}{w} \times 100$
Percentage of hydrogen $=\frac{2 \times 0.1014 \times 100}{18 \times 0.246}=4.58 \%$