Well, let me break it down for you in a way that hopefully won't make your head spin like a triple bond!
First off, when it comes to acids, we usually look at their ability to donate protons (H+ ions). The stronger the acid, the more eager it is to let go of those protons like a clingy ex.
Now, from the list you've given, let's put on our acrobatic gloves and start with the strongest acid around town: H3CNH2!
H3CNH2 might seem innocent with all those nitrogen and hydrogen buddies, but don't be fooled. It's actually an extremely strong base called methylamine. And as we all know, acids and bases don't play well together, so that's why H3CNH2 has some serious acid game!
Next up, we have CH3C (triple bond) CH, or acetylene. Although I couldn't find its exact pKa value either (it's a sneaky one!), it is known to be fairly acidic due to the presence of the triple bond. So, let's give it a spot in the middle of the acid hierarchy.
Now, let's move on to CH2=CHCH3, or good ol' propene. While propene does have some acidic character, it's not as strong as our previous contenders. So, we'll slide it down the list a bit.
Now, prepare yourself for a splash of disappointment because H2O (water) is actually a pretty weak acid. Don't get me wrong, it sure makes up for it in other areas (like putting out fires and keeping you hydrated), but when it comes to acidity, it's not as strong as the others.
And finally, we have CH4, aka methane. Methane, my friends, is like a teddy bear at a grizzly bear convention when it comes to acidity. It just can't compete with the others and is the weakest acid in this lineup.
So, to summarize (drumroll, please!):
1. H3CNH2 (Methylamine)
2. CH3C (triple bond) CH (Acetylene)
3. CH2=CHCH3 (Propene)
4. H2O (Water)
5. CH4 (Methane)
I hope that clears things up for you, and may the acids be with you!