Explaining pH: pH in a nutshell!

The pH scale is used to measure and report whether a solution is acidic, basic (alkaline), or chemically neutral. The pH scale is numbered 0-14; at room temperature, 25°C, below 7 means the solution is acidic, 7 means the solution is chemically neutral, and above seven means the solution is basic. Each unit on the pH scale has a tenfold difference in acidity or alkalinity than the unity above or below. In order to measure pH, litmus (vegetable dye) paper is used. After applying a few drops of a solution or dipping the paper in a solution, if the paper turns blue, the solution is basic, and if the paper turns red, the solution is acidic. Concentrated acids and bases react chemically with many other substances, and they often corrode, or eat away at, materials. Most acids are made up of one or more hydrogen (H) atoms, and bases generally include hydroxide ions (OH-). Although ammonia and baking soda do not contain hydroxide ions, since they react with water to generate hydroxide ions, they produce basic solutions. Acidic and basic solutions affect living organisms. For example, low pH (acidity) in water can impair fish-egg development and cause increased concentrations of metal ions in natural waters. High pH (basic contamination) dissolves organic materials, like skin and scales.
Additionally, although 7 is the ideal pH for drinking water, the EPA allows drinking water to be in the range of 6.5-8.5 pH.