If a gaseous mixture contains $20\%$ $H_2$ by weight,what is the number of moles of $H_2$ in $100 \ g$ of the mixture (in $mol$)?

$A$ flask contains $98 \ mg$ of $H_2SO_4$. If $3.01 \times 10^{20}$ molecules of $H_2SO_4$ are removed from the flask,the number of moles of $H_2SO_4$ remaining in the flask is $\left(N_A = 6.02 \times 10^{23}\right)$

Number of moles and number of molecules in $1.4187 \ L$ of $SO_2$ at $STP$ respectively are:

Numbers of gram atoms of oxygen present in $0.8 \ mol$ of $C_4H_6O_6$ would be

The number of moles of electrons in $1 \ kg$ of electrons is .......

Which of the following contains the maximum number of atoms?