Final answer:
The errors that can occur when measuring pH with a glass combination electrode are incorrect calibration, contamination of the electrode, and electrode aging. The correct answer is that all of these can happen, hence 'All of the above'.
Step-by-step explanation:
When measuring the pH with a glass combination electrode, several errors can occur. These errors include:
- Incorrect calibration: Without proper calibration using a standard solution of known pH, the pH readings can be inaccurate.
- Contamination of the electrode: If the glass electrode is contaminated with substances from previous measurements, it can give incorrect results.
- Electrode aging: Over time, the electrode's performance degrades, which can lead to less accurate pH readings. It's important to recognize that all these factors can contribute to errors in pH measurement.
Therefore, the correct answer is d) All of the above.