Which member of each pair listed follows the ideal gas law more closely?
Give the reason for each prediction, using the kinetic molecular theory.


i. H2 (g) or HI (g)

ii. A gas at 100 degrees C or 100 K

iii. A gas under a pressure of 1.0 atm or the same gas under a pressure of 10.0 atm

I don't know how to go about explaining this?  

Gases behave more ideally if they have less or negligible intermolecular forces of attractions(IMF).So you need to check
which gas has minimum IMF in the given options
1) H2 has only dispersion forces and HI has polar forces also
hence H2 gas will follow ideal gas law more closely
2)Ideal behavior is more applicable at high temp because at high temp molecules are moving faster and have minimum attractions or less IMF
100K is less then 373K or 100 deg C
so the answer is ---
so now you can guess your answer
3) IDEAL GASES have minimum IMF at low Pressure because molecules are more away from each other and have minimum IMF
so the answer is ---

    Thank you so much Ms. Sharma!!!! That really helps! Thank you!! Is it ok if I ask you other doubts I might have?

sure pl

Ok...thanks once again Uma Aunty! I have a question regarding the same topic...in fact, it's another question in this series of questions...what is the critical temperature of a gas exactly? The part 4 of this same question was:

Which one is follows the ideal gas law more closely:--- a gas with a critical temperature of 100 K or one with a critical temperature of 300 K? I'm just confused as to what the critical temperature is...Sorry I forgot to ask this question in my original post...Thank you for your help!!!

Critical temp is the temp above which no gas can be liquified whatever is the pressure .Substances with low IMF have low critical temp
like N2 gas is around -147deg C and H2O is 373 deg C (approx)
it is easy to liquify gases with high IMF .Pl try to answer your question according this concept.

That helps a lot! I understand no that the gas with the critical temperature of 100 K is the one closest to the Ideal Gas Law. Because lower critical temper = lower imf = closer to Ideal Gas behavior.

perfect