PH

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The title of this article is wrong due to some limitations. The right title is pH.

pH (Power of Hydrogen) is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. The lower the pH, the more acidic is the solution. The higher the pH, the more alkaline is the solution. Substances which are neither acidic (neutral) usually have a pH of 7. Acids have a pH less than 7. Alkalis have a ph greater than 7.

In fact, pH is a measure of the concentration of protons (H+) in a solution. S.P.L. Sørensen introduced this concept in 1909. The p stands for the German potenz, meaning power or concentration, and the H for the hydrogen ion (H+).

The formula for calculating pH is:

\mbox{pH} = -\log_{10} \left[ \mbox{H}^+ \right]

[H+] indicates the concentration of H+ ions (also written [H3O+], concentration of the equivalent hydronium ions), measured in moles per litre (also known as molarity).

Most substances have a pH in the range 0 to 14, although extremely acidic or basic substances may have pH < 0, or pH > 14.

Basic substances have, instead of Hydrogen ions, a concentration of Hydroxide ions (OH-).

[edit] Some common pH values

pH
Battery acid 1.0
Stomach 2.0
Lemon juice 2.4
Cola 2.5
Vinegar 2.9
Orange or apple juice 3.5
Beer 4.5
Coffee 5.0
Tea 5.5
Acid rain < 5.6
Milk 6.5
Pure water 7.0
Blood 7.34 - 7.45
Sea water 8.0
Hand soap 9.0 - 10.0
Household ammonia 11.5
Bleach 12.5
Household lye 13.5


[edit] Neutralisation

Neutralisation can be summed up by the formula:

H+ + OH- = H2O

(acid + alkali = water)

[edit] See also