Suggested pH of Standard Solutions

The standard buffer solutions have been developed in a way so that each of them should have (1) inexpensive chemicals, (2) simple recipe, and (3) reproducibility and stability in time. 

The standard buffer solutions presented in Table 1.4 cover a wide range of pH from 1 to 13 so that a pH sensor can be calibrated and used at any pH in this range. 

It should be mentioned that the common pH values of aqueous solutions at 25°C and 1 bar are between 1 and 13, while pH of a high concentrated acid can be 1 and 

When measuring pH, the activity of H+(aq) [or OH (aq)] ions can experimentally be obtained. A calibration approach using a number of buffer solutions should be used in such measurements. 

An aqueous solution, which consists of a coupled weak acid and salt or weak base and salt when such a solution is resisting to pH changes upon small addition of add or base, represents an example of the buffer solution. To measnre pH, a set of standard (buffer) solutions should be used to calibrate pH sensor. The compositions of buffer solutions are well known, and they cover a wide range of pH from 1 to 13. 

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