Hydrogen ion exponent

For many purposes, especially when dealing with small concentrations, it is cumbersome to express concentrations of hydrogen and hydroxyl ions in terms of moles per litre. A very convenient method was proposed by S. P. L. Sorensen (1909). He introduced the hydrogen ion exponent pH defined by the relationships ... 

Hydrogen ion exponent — Obsolete term for the numerical value of - pH used by - Serensen. 

Its value is often quoted instead of that of K. The usefulness of pK will become apparent when dealing with the hydrogen-ion exponent or pH. 

THE HYDROGEN-ION EXPONENT (pH) In the practice of chemical analysis one frequently deals with low hydrogen-ion concentrations. To avoid the cumbersome practice of writing out such figures with factors of negative powers of 10, Sorensen (1909) introduced the hydrogen-ion exponent or pH, defined by the relationship ... 

The hydrogen ion exponents of a number of aspartic acid solutions are given in the following table. The [H+] values were calculated in three ways by the simple equation (8), by the second approximation method, and by the complicated equation (9) of Soeensen. 

Soren Peer Lauritz Sorensen (1868—1939). Danish biochemist. Sorensen originally wrote the symbol as pjj and called p the hydrogen ion exponent (Wasserstoffionexponent), it is the initial letter of Potenz (German), puissance (French), and power (English). It is now customary to write the symbol as pH. 

The principles of pH begin with a definition of the term pH. The p comes from the word power. The H, of course, is the symbol for the element of hydrogen. Together, the term pH means the hydrogen ion exponent. 

The above method of expressing the acidity or alkalinity of a solution has given place to another still more simple and convenient method. It was introduced by Sorensen in 1990. In this method, hydrogen ion concentration is expressed in terms of hydrogen ion exponent, Le., a number obtained by giving a positive value to the n ative power of 10 in the expression 1 x 10 . This was originally represented as Ph but now most suitably written as pH. Thus,... 

The term pH is based on p, for power, and H, representing the element of hydrogen. Therefore, pH means the hydrogen ion exponent and pH is a measure of acidity of a solution. The well-known definition of pH can be shown as ... 

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