Which chemical is used as a standard for measuring conductivity?

Potassium Chloride is commonly used as a standard for measuring conductivity due to its well-characterized dissociation properties in water, resulting in reliable ionic strength that can be easily reproduced in laboratory settings. Potassium ions (K+) and chloride ions (Cl-) both provide significant contributions to electrical conductivity, making this compound a suitable reference.

In laboratory practices, Potassium Chloride solutions are specifically prepared with known concentrations, allowing for accurate calibration of instruments that measure conductivity. This is essential because consistent standards ensure that measurements can be compared across different tests and laboratories, aiding in quality control and compliance with regulatory standards for drinking water analysis.

The other chemicals listed, while they have their own applications in analytical chemistry, do not serve the same consistent role in conductivity measurement. Sodium Chloride is also used in some contexts, but Potassium Chloride is often preferred for its stability and reliability in providing a clear baseline.