reference value pH standard

An aqueous solution of $0.05 mol$ potassium hydrogen phthalate per kg water which is the reference value for the definition of pH(RVS) values in the temperature range $0$ - $95 °C$ .

See also: operational pH standard, primary pH standard

Source:

PAC, 1985, 57, 531 (Definition of pH scales, standard reference values, measurement of pH and related terminology (Recommendations 1984)) on page 540