Pure Water Question~~?

Question

Is Pure water an acid or base? explain plz plz plz.

Answer 1

Autoionization of Water
Since we have the ability to measure pH for acid solutions, we can measure pH for pure water as well. It might seem that this would make no sense, as we would expect [H3O+] to equal zero exactly in pure water. Surprisingly, this is incorrect: a measurement on pure water at 25°C yields pH=7, so that [H3O+]=1.0×10-7M. There can be only one possible source for these ions: water molecules. The process
H2O(l)+H2O(l)→H3O+(aq)+OH−(aq)(6)
is referred to as the autoionization of water. Note that, in this reaction, some water molecules behave as acid, donating protons, while other acid molecules behave as base, accepting protons.
Since at equilibrium [H3O+]=1.0×10-7M, it must also be true that [OH−]=1.0×10-7M. We can write the equilibrium constant for equation 6, following our previous convention of omitting the pure water from the expression, and we find that, at 25°C,
Kw = [H3O+][OH−]
= 1.0×10-14M
(7)
(In this case, the subscript "w" refers to "water".)
equation 6 occurs in pure water but must also occur when ions are dissolved in aqueous solutions. This includes the presence of acids ionized in solution. For example, we consider a solution of 0.1M acetic acid. Measurements show that, in this solution [H3O+]=1.3×10-3M and [OH−]=7.7×10-12M. We note two things from this observation: first, the value of [OH−] is considerably less than in pure water; second, the autoionization equilibrium constant remains the same at 1.0×10-14. From these notes, we can conclude that the autoionization equilibrium of water occurs in acid solution, but the extent of autoionization is suppressed by the presence of the acid in solution.
We consider a final note on the autoionization of water. The pH of pure water is 7 at 25°C. Adding any acid to pure water, no matter how weak the acid, must increase [H3O+], thus producing a pH below 7. As such, we can conclude that, for all acid solutions, pH is less than 7, or on the other hand, any solution with pH less than 7 is acidic.

Answer 2

Autoionization of Water

Answer 3

well if its 100% pure water it has a pH of 7 making it neither. however when it becomes in contact with even the slightest amount of air the carbon dioxide becomes absorbed in the water making it ever so slightly acidic.

Answer 4

water has properties called PH, and it can be either alkaline, or high in disolved solids, or have a high PH. The trick is to find the right balance of all the factors. Many for people have 'soft water' than 'hard water" soft being alkaline, hard having too much dissolved solids, which leads to scale.

Answer 5

tap is acidic, pure water is neutral.