Does Temperature Affect the pH Value?

As per USP (24 ± 2°C), BP (20-25°C) and other pharmacopeia, the pH of the sample/substance was measured at the temperature near by 25°C. Because temperature plays a crucial role in the pH of the substance.

How the temperature changes the pH value:

pH is defined as the negative logarithm of H+ ion concentration. It is revealed that the power of hydrogen ion concentration present in the sample. pH of the sample is inversely proportional to the temperature. Likewise, if the temperature rises in the solution, the level of pH is decreased. Otherwise the pH of the solution is increased while it get low temperature.

Temperature affect the pH in many ways like affecting sample or affecting the electrode. This is possible through the way of dynamic equilibrium of solution (Le Chaterlier’s principle)

If the temperature rises, more hydrogen ion produced from the sample that can be forced to absorb heat. Then the pH of the sample is decreased due to high concentration of hydrogen ion during High temperature. These same principle is followed while the temperature gets low (high pH value)

During the experiment, neutral pH was measured as 7 at the range of 25°C. If the temperature rises or is low in solution, it becomes a slight change in pH value.

So as per USP, pH was measured at the temperature within the range of 24±2°C for better output.


Read also: Validation of pH Measurement Testing


Resource Person: SAKTHIVEL MURUGAN NATARAJAN

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *