In the crystalline solid $MSO_{4} \cdot nH_{2}O$ of molar mass $250 \ g \ mol^{-1}$, the percentage of anhydrous salt is $64$ by weight. The value of $n$ is

The percentage of $Se$ in peroxidase enzyme is $0.5\%$ by mass (atomic mass of $Se = 78.4 \ amu$). Then,the minimum molecular mass of enzyme which contains not more than one $Se$ atom is

In an organic compound,the weight ratio of $C$,$H$,and $N$ atoms is $9 : 1 : 3.5$. If the molecular weight of the compound is $108$,what is its molecular formula?

An organic compound containing carbon and hydrogen has an empirical formula of $CH_2$. The mass of $1 \ L$ of this organic gas is equal to the mass of $1 \ L$ of $N_2$ gas at the same temperature and pressure. What is the molecular formula of the organic gas?

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 $:$

$C_4H_6O_2$ does not represent :