When calibrating a thermometer, how far can it differ from the reference thermometer before it must be discarded?

The correct choice indicates that a thermometer can have a variance of up to 1 degree Celsius from the reference thermometer before it is deemed unusable. This standard is often based on the acceptable limits of accuracy for many laboratory instruments to ensure reliable measurements.

In practical applications, maintaining a close calibration is essential for producing valid and reproducible results, especially in a laboratory setting where even small temperature discrepancies can affect reactions, solubility, and other critical parameters.

Thermometers that deviate more than 1 degree Celsius could lead to significant errors in temperature-sensitive analyses and might compromise the integrity of the test results. Consequently, a divergence beyond this threshold indicates a need for replacement to uphold the quality and accuracy of laboratory work.

Parameters like these are typically determined by standard operating procedures, guidelines from regulatory agencies, and best practices within the laboratory. This ensures that all thermometers used in measurements remain precise enough for accurate data collection.