You can solve this question using ideal gas formula. There are a few factors that will determine the volume(V) of gas, the number of the gas molecules (n), pressure(P), and temperature(T). You also need coefficient (R) which will depend on the unit used in pressure. We will use R= 0,08206 L atm K-1 mol-1 here. Don't forget to change the Celcius temperature into Kelvin.
The bond length from the values inside the atomic radii is calculated according to the query. This would be the upper limit of a molecule's binding length.
