The molar volume of any gas at STP is

•  At STP, the gas is at 273K temperature and 1 atm pressure.
• Now, by applying the ideal gas equation relating the pressure(P), volume(V), and atmospheric temperature(T), we can find out the molar volume of any gas at STP.
• The ideal gas equation is as follows;

                  PV = nRT,

 where n is the number of moles(1) and R is the gas constant (8.314 J/molK).

• Now, by substituting the values at STP in the ideal gas equation we get;

    $\mathrm{V}=\frac{\mathrm{nRT}}{\mathrm{P}}=\frac{1\times 8.314\times 273}{1.1013\times {10}^5}=0.0224{\mathrm{m}}^3=22.4 \mathrm{liters}$

Thus, the molar volume of any gas at STP is calculated to be 22.4 liters.