The number of molecules at $NTP$ in $1 \ mL$ of an ideal gas will be

Two flasks $A$ and $B$ of $500 \ mL$ each are filled with $O_2$ and $SO_2$ respectively at $300 \ K$ and $1 \ atm$ pressure. Then the flasks contain:

Which of the following contains the maximum number of molecules?

The number of gram atoms of oxygen present in $0.3 \ mol$ of $(COOH)_2 \cdot 2H_2O$ is

The number of electrons in a mole of hydrogen molecule is

How many molecules are present in $22400 \ cm^3$ of a gas at $STP$?