pH: In chemistry, pH is a numeric scale used to specify the acidity or alkalinity of an aqueous solution. It is the negative of the logarithm to base 10 of the activity of the hydrogen ion. Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are alkaline or basic. Pure water has a pH of 7 and is neutral, being neither an acid nor a base.
pH measurements are important in medicine, biology, chemistry, agriculture, forestry, food science, environmental science, oceanography, civil engineering,chemical engineering, nutrition, water treatment & water purification, and many other applications.
Examples of our bodies pH include our skin which has a normal acid level, whereas our urine will vary daily. Our blood remains between a pH of 7.34 to 7.45.