Question

what makes pure water neutral?

Answer 1

Pure water, H2O, dissociates. When it dissociates it does so into H+ (acid) and OH- (base) in equal amounts. So in pure water there is only H2O, H+ and OH-, since the H+ and OH- 'cancel out' it is neither acidic or basic.

If you are taking Solution Chemistry this thought can be represented as
Kw=[H+][OH-]=[10E-7 H+][10E-7 OH-]

Where Kw=10E-14 is the dissociation constant for water

Note: H+ is interchangeable with H3O+

Answer 2

That's correct!

Answer 3

Because of their equal amount of base and an acid!