For a pH test using an electrode, which practice is recommended?

For a pH test using an electrode, which practice is recommended?

• A. Raise temperature to 40°C
• B. Maintain constant stirring rate
• C. Lower temperature to 2°C
• D. Dechlorinate

Answer: (B)

Accurate pH measurement with a glass electrode depends on having a uniform sample at the electrode surface. If the liquid isn’t well mixed, the electrode can encounter microenvironments with different hydrogen ion activity, causing unstable readings and slow response. Keeping the stirring rate constant creates a homogeneous solution around the probe, so the measured pH reflects the entire sample and readings are steady and repeatable. Temperature also matters because pH and electrode response shift with temperature, so extreme or fluctuating temperatures should be avoided; that’s why altering temperature to very high or very low values isn’t recommended. Dechlorinating isn’t necessary for pH measurement, so it doesn’t influence the electrode reading.

Accurate pH measurement with a glass electrode depends on having a uniform sample at the electrode surface. If the liquid isn’t well mixed, the electrode can encounter microenvironments with different hydrogen ion activity, causing unstable readings and slow response. Keeping the stirring rate constant creates a homogeneous solution around the probe, so the measured pH reflects the entire sample and readings are steady and repeatable. Temperature also matters because pH and electrode response shift with temperature, so extreme or fluctuating temperatures should be avoided; that’s why altering temperature to very high or very low values isn’t recommended. Dechlorinating isn’t necessary for pH measurement, so it doesn’t influence the electrode reading.