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potential of hydrogen; a measure of the acidity or alkalinity of a solution equal to the common logarithm of the reciprocal of the concentration of hydrogen ions in moles per cubic decimetre of solution. Pure water has a pH of 7, acid solutions have a pH less than 7, and alkaline solutions a pH greater than 7
A term used to describe the hydrogen-ion activity of a system; it is equal to -log aH+; here aH+is the activity of the hydrogen ion; in dilute solution, activity is essentially equal to concentration and pH is defined as -log10[H+], where H+is hydrogen-ion concentration in moles per liter; a solution of pH 0 to 7 is acid, pH of 7 is neutral, pH over 7 to 14 is alkaline.
A measure of the acidity or alkalinity of a solution; numerically equal to 7.0 for a neutral solution; the pH value increases with increasing alkalinity and decreases with increasing acidity. Also See pH value.
1. On drawings, abbr. for phase.
2. Abbr. for phillips head.
A unit of illumination equal to 1 lumen per square centimeter. Abbr. ph.
The country code for the Philippines.