Number of $g$ of oxygen in $32.2\,g$ of $Na_2SO_4 \cdot 10H_2O$ is

The empirical formula of a compound is $C_2H_5O$ and its molecular weight is $90$. The molecular formula of the compound is:

If $1.24 \ g$ of $P$ is present in a $2.2 \ g$ sample of a compound,identify the empirical formula of the compound (Atomic mass of $P = 31 \ g/mol$,$S = 32 \ g/mol$).

$A$ compound contains $10^{-2} \%$ of phosphorus. If the atomic mass of phosphorus is $31$,the molecular mass of the compound having one phosphorus atom per molecule is :-

An organic compound contains $C = 40\%$,$H = 13.33\%$,and $N = 46.67\%$. Its empirical formula is:

On combustion,$0.210 \ g$ of an organic compound containing $C$,$H$,and $O$ gave $0.127 \ g$ $H_2O$ and $0.307 \ g$ $CO_2$. The percentages of hydrogen and oxygen in the given organic compound respectively are $:$