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S. P. L. Sørensen. Søren Peter Lauritz Sørensen (9 January 1868 – 12 February 1939) was a Danish chemist, known for the introduction of the concept of pH, a scale for measuring acidity and alkalinity .
The pH range is commonly given as zero to 14, but a pH value can be less than 0 for very concentrated strong acids or greater than 14 for very concentrated strong bases. [2] The pH scale is traceable to a set of standard solutions whose pH is established by international agreement. [3]
Beckman model 72 pH meter, 1960. 781 pH/Ion Meter pH meter by Metrohm. A pH meter is a scientific instrument that measures the hydrogen-ion activity in water-based solutions, indicating its acidity or alkalinity expressed as pH. [ 2] The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode ...
Universal indicator. A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution. [ 1]
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH ( acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. [ 1] Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O +) or hydrogen ions (H +) in the ...
The pH was lowered by the addition of phosphoric acid and the resulting liquid was cooled. [67] Chain determined that penicillin was stable only with a pH of between 5 and 8, but the process required one lower than that. By keeping the mixture at 0 °C, he could retard the breakdown process. [68]
Linderstrøm-Lang began in the Carlsberg laboratory under its second director S. P. L. Sørensen (who invented the pH scale). 1949 volumetric studies showing that the interior of proteins has very few charges and, hence, is likely to be hydrophobic.
An acid–base titration is a method of quantitative analysis for determining the concentration of Brønsted-Lowry acid or base (titrate) by neutralizing it using a solution of known concentration (titrant). [ 1] A pH indicator is used to monitor the progress of the acid–base reaction and a titration curve can be constructed.