Question

Pure water is neutral. What is the appropriate justification for this?

Answer 1

ater is neither an acid or a base, having the pH of 7.0.

Answer 2

The fast smart man would fast ask: WHY does water have a pH of 7.0 at 25 degrees C?

Answer 3

Surely the reason to water being "natural" lies in the definition of pH being 7.0.

Answer 4

But there is deeper meaning.

Answer 5

Ok let me help a bit on the way. What does it mean when we say that pH is equal to 7?

Answer 6

Ok. You can take care of the question.

Answer 7

It has the same number of hydroxide ions and hydronium ions.

Answer 8

Okay let me answer then:
We consider water natural at 25 degrees C due there are a equal amount of protons and hydroxide ions.
We know that water makes autoprotolysis and that the product of the proton and hydroxide concentration is always equal to each other and with a very specific value at 25 degrees C.
\[\Large \sf \left[ H^+ \right]=\left[ OH^- \right]=1.0 \times 10^{-7} M\]
In other words we get water's self autoprotolysis constant to:
\[\Large K _{v}=\left[ H ^{+} \right] \left[ OH^- \right] = 1.0 \times 10^{-14} \sf M^2\]
So this means there are equally much "base (OH)" and "acid (H)" making it "natural" making the very fundamental for the pH scale:
\[\Large pH=-\log[H]\]
For water at 25 degrees C:
\[\Large pH=-\log(1.0 \times 10^{-7})=7\]

Answer 9

@csheveland thank you, what I wanted to get forward :)

Answer 10

You can fast do the pOH too:
\[\Large pOH=-\log[OH^-]\]
\[\Large pOH=-\log(1.0 \times 10^{-7})=7\]

Answer 11

copy and paste copy and paste

Answer 12

What do you mean with that?

Answer 13

if you mean I am turning to plagiarism, then I suggest you can provide a proof that I am using others work. Also this is old and now common knowledge, so the need for references I consider unnecessary.

Answer 14

"water is neither an acid or a base.."

Um water is both, an acid AND a base.

Answer 15

I wasn't suggesting that you were plagiarizing. I did not have any intentions to falsely accuse you.