Acids and Bases

PH is short for the power of Hydrogen. It's the measure of acidity or alkalinity in a solution. In pure water at 77°F, The hydrogen ions are equal to the concentration of hydroxide ions. This is the "neutral" marking and means the pH level is 7.0.

In solutions where the hydrogen ions exceed the concentration of hydroxide ions, the pH falls below 7.0 and is an acid.

In solutions where the hydroxide ions exceed the concentration of hydrogen ions, the pH rises above 7.0 and is a base. The pH of a substance tells if it's an acid, neutral, or a base.

With all deference to the asker and to the previous answerer, technically substances don't have pH's. Aqueous solutions have pH's, and the pH tells you (on a logarithmic scale) the concentration of H+ (or more precisely H3O+) in that solution. A substance is an acid if it lowers the pH of a solution when it is dissolved. It does this by donating protons (H+'s) to water molecules to create more H3O+. A substance is a base if it increases the pH of a solution by accepting a proton from water molecules to form OH-. H3O+ and OH- are in equilibrium with each other in solution, so the more OH- you create, the less H3O+ will be in solution and the higher the pH. So a better answer to the question is that "The pH of a solution tells you if its an acidic, neutral, or basic solution."


pH is the cologarithm of the activity of dissolved H+ (or sometimes written H3O+) ions (aka. Protons) in a solution, and measures the acidity/basicity of it. The Danish chemist Søren Peder Lauritz Sørensen came up with the idea in 1909.

* The p in pH has an unknown meaning, but is accepted to mean 'power' or 'potential'. * A pH of 7.0 is said to be neutral, and pure water in standard conditions is a pH of 7. * A pH of less than 7 is acidic, and a pH of more than 7 is basic. * The pH scale usually ranges from 0 to 14, but negative values have been observed. * H2SO4 (sulfuric/battery acid) is extremely acidic, and NaOH (caustic soda/lye) is extremely basic. * pH= -log[H+]



The pH scale measures the hydrogen ion concentration of a substance. A low pH indicates an acidic substance with many H ions while a high pH indicates a basic substance containing few H ions.
ph is the abbreviation for Philippines.