In a compound formed by element $X$ (atomic mass = $75$) and element $Y$ (atomic mass = $16$),if the percentage of $X$ is $75.8\%$,what will be its empirical formula?

An organic compound contains $C$,$H$ and $S$. The minimum molecular weight of the compound containing $8\%$ sulphur is........$g\,mol^{-1}$ (atomic weight of $S = 32\,amu$)

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

The empirical formula of a crystalline iron compound is $Fe_2(SO_4)_3$. It is used in water and sewage treatment to remove suspended impurities. The percentage composition of iron,sulfur,and oxygen in this compound is respectively......

$A$ compound $X$ contains $32 \%$ of $A$,$20 \%$ of $B$,and the remaining percentage of $C$. Then,the empirical formula of $X$ is:
(Given atomic masses of $A = 64$,$B = 40$,$C = 32 \ u$)

The value of $x$ in $KAl(SO_4)_x \cdot 12 H_2O$ is $.....$