What is the Difference Between Calculated pH and Experimental pH?

The difference between calculated pH and experimental pH lies in the method used to determine the value. Calculated pH is derived using the pH equation, while experimental pH is determined using a pH meter by measuring the sample directly. Here are the key points:

• Calculated pH: This value is calculated using the pH equation, which is based on the concentration of hydrogen ions (protons) and hydroxide ions in a solution.
• Experimental pH: This value is determined using a pH meter, which measures the electrical potential difference between two electrodes immersed in the solution.

There are several reasons why the calculated pH and experimental pH may differ:

1. Presence of impurities or contaminants: The presence of impurities or contaminants in the sample can affect the experimental pH, leading to a discrepancy between the calculated and experimental values.
2. Human and instrumental errors: Errors in measurement, preparation of solutions, or calibration of the pH meter can contribute to differences between calculated and experimental pH values.
3. Temperature and pressure: The pH of a solution can be affected by temperature and pressure, which may not be accounted for in the calculated pH.
4. Concentration of other ions: The presence of other ions in the solution, such as potassium ions or chloride ions, can also affect the experimental pH.

In summary, calculated pH is derived using the pH equation, while experimental pH is determined using a pH meter. Differences between the two values can arise due to the presence of impurities or contaminants, human and instrumental errors, temperature and pressure, and the concentration of other ions in the solution.

Comparative Table: Calculated pH vs Experimental pH

The difference between calculated pH and experimental pH can be summarized as follows:

It is essential to compare calculated and experimental pH values to evaluate the accuracy of theoretical predictions and to understand the behavior of solutions under different conditions. This comparison can also help identify any discrepancies between the theoretical and experimental values, which may be due to factors such as experimental errors, instrumental limitations, or the presence of other ions in the solution.