B because it can stabilize
I believe dimensional analysis
C. NO2 is covalent. Hope this helps!
Gravity is caused by a magical force
There are other ions that make acidic and basic solutions, but we won't be talking about them here. That pH scale we talked about is actually a measure of the number of H + ions in a solution. If there are a lot of H + ions, the pH is very low.
Hope I helped :)