Relationship With The Neutral Point of Water
Water molecules dissociate into equal amounts of H3O+ and OH−, so their concentrations are equal to 1.00 × 10−7 mol∙dm−3 at 25 °C. A solution in which the H3O+ and OH− concentrations equal each other is considered a neutral solution. In general, the pH of the neutral point is numerically equal to pKw/2.
Pure water is neutral, but most water samples contain impurities. If an impurity is an acid or base this will affect the concentrations of hydronium ion and hydoxide ion. Water samples which are exposed to air will absorb the acid carbon dioxide and the concentration of H3O+ will increase. The concentration of OH− will decrease in such a way that the product remains constant for fixed temperature and pressure.
Read more about this topic: Self-ionization Of Water
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—Edward Hoagland (b. 1932)
“Henry David Thoreau, who never earned much of a living or sustained a relationship with any woman that wasnt brotherlywho lived mostly under his parents roof ... who advocated one days work and six days off as the weekly round and was considered a bit of a fool in his hometown ... is probably the American writer who tells us best how to live comfortably with our most constant companion, ourselves.”
—Edward Hoagland (b. 1932)
“The United States must be neutral in fact as well as in name.... We must be impartial in thought as well as in action ... a nation that neither sits in judgment upon others nor is disturbed in her own counsels and which keeps herself fit and free to do what is honest and disinterested and truly serviceable for the peace of the world.”
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—Bible: New Testament, Matthew 27:24.