An organic compound contains $49.3\%$ carbon,$6.84\%$ hydrogen and its vapour density is $73$. The molecular formula of the compound is:

By usual analysis, $1.00 \ g$ of compound $(X)$ gave $1.79 \ g$ of magnesium pyrophosphate. The percentage of phosphorus in compound $(X)$ is: (nearest integer)
(Given, molar mass in $g \ mol^{-1}$; $O=16, Mg=24, P=31$)

$120 \ g$ 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 ...... .

Hemoglobin contains $0.334 \% \, Fe$ by weight. If the molecular mass of hemoglobin is approximately $67200 \, g/mol$,determine the number of iron atoms in one molecule of hemoglobin. (Atomic mass of $Fe = 56 \, g/mol$)

$0.765 \ g$ of an acid gives $0.535 \ g$ of $CO_2$ and $0.13 \ g$ of $H_2O$. The ratio of the percentage of $C$ and $H$ is:

The molecular formula of a compound is $X_4O_6$. If $10 \ g$ of the compound contains $5.62 \ g$ of $X$,what is the approximate atomic mass of $X$ in $amu$?