The empirical formula of a compound is $C_2H_5O$ and its vapour density is $45$. What is the molecular formula of the compound?

$A$ protein $'A'$ contains $0.30\, \%$ of glycine (molecular weight $75$). The minimum molar mass of the protein $'A'$ is $.......\, \times 10^{3} \, g\, mol^{-1}$ [nearest integer]

The percentage of $N_2$ in urea is about

$0.102 \ g$ of an organic compound $X$ was oxidised with fuming nitric acid. The resulting solution,after reaction with excess of aqueous $BaCl_2$,produced $0.233 \ g$ of $BaSO_4$ as a precipitate. Compound $X$ is likely to be: [Given: Atomic wt. of $Ba = 137$]

In a substance,the number of atoms of $Cr$ and $O$ are $4.8 \times 10^{10}$ and $9.6 \times 10^{10}$ respectively. The empirical formula of the substance is .......

On analysis,a certain compound was found to contain iodine and oxygen in the ratio of $254 \ g$ of iodine and $80 \ g$ of oxygen. The atomic mass of iodine is $127$ and that of oxygen is $16$. Which of the following is the formula of the compound?