Which substance would most behave as an ideal gas at stp a. n2 b. h2o c. ch3oh d. hf

A. N2 Let's look at the substances and see which would be likely to be a near ideal gas at STP. A. N2 * Nitrogen gas. It's a gas at 273.15 K and is fairly non-reactive. This is a very good candidate for the correct answer. B. H2O * Water. There is some H2O in gaseous form, but it's more likely to be a solid or liquid. This isn't a good candidate, so it's the wrong answer. C. CH3OH * Methanol. Fairly large molecule and has a boiling point well above that of 273.15 K. So it's more likely to be a liquid. So also the wrong answer. D. HF * Hydrogen fluoride. Not a nice chemical to deal with. And a boiling point of 340.25 K which is much higher than the 273.15 of STP. Not the right answer. Of the 4 candidates, only N2 has a boiling point well below the 273.15 K of STP and is the only substance listed that will be completely a gas at STP. So that's the correct answer.