In a compound,$C, H,$ and $N$ are present in the weight ratio of $9:1:3.5$. If its molecular weight is $108$,then its molecular formula will be:

$120 \ g$ of an organic compound that contains only carbon and hydrogen gives $330 \ g$ of $CO_{2}$ and $270 \ g$ of water on complete combustion. The percentage of carbon and hydrogen,respectively,are ...... .

$A$ gaseous hydrocarbon gives upon combustion $0.72 \ g$ of water and $3.08 \ g$ of $CO_{2}$. The empirical formula of the hydrocarbon is:

Which one has the highest percentage of nitrogen?

An oxide of iron,which contains $69.9 \%$ iron and $30.1 \%$ dioxygen by mass,has the empirical formula:

$A$ hydrocarbon contains $80\%$ carbon and its vapor density is $15$. What is the hydrocarbon?