Which statement about pH meters is NOT true?

The reason why the statement about pH meters needing to be used only when contaminants are known is not true lies in the versatility and application of pH meters in various scenarios. pH meters are valuable analytical tools that can assess the acidity or alkalinity of a solution, making them crucial in both known and unknown environments.

In many cases, a pH meter can be used to gather data on a solution's pH without prior knowledge of its contaminants. This feature is particularly useful in environmental monitoring, waste management, and even agricultural practices, where assessing the pH of a sample can be essential for determining soil health, potential contamination, or preparing for further chemical analysis.

The ability to provide real-time measurements is another essential aspect of pH meters, allowing for immediate insight into the chemical properties of substances being tested. Moreover, their applicability across different environments underscores their importance as robust instruments in both fieldwork and laboratory settings.