Consider three 1 l flasks at stp. flask a contains nh3 gas, flask b contains no2 gas, and flask c contains n2 gas. which contains the largest number of molecules? in which flask are the molecules least polar and therefore most ideal in behavior?

1 mole of gas occupies 22.4 L at STP. Therefore, each gas has 1/22.4 moles and because the number of moles is the same, the number of molecules of each gas is also the same.

The least polar molecules are of N₂ and they will show the most ideal behavior out of all three of the gases. 

The correct answer is "hydrogen".