Which electrode is used to measure pH?

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Multiple Choice

Which electrode is used to measure pH?

A glass membrane electrode measures pH. Its thin glass bulb is selectively permeable to hydrogen ions, so a potential develops at the glass–solution interface that changes with hydrogen ion activity (pH). When you compare this sensing electrode to a stable reference electrode, the measured potential tracks pH, with a typical slope of about 59 mV per pH unit at room temperature. This makes it the standard tool for pH measurement because the glass responds specifically to H+ and provides a reliable, reproducible signal. Other options describe sensors that aren’t designed for monitoring hydrogen ion activity—one is a polymer-based sensor for other targets, another is a solid-state crystal sensor used in different contexts, and the gas-sensing electrode is for gases, not aqueous pH.

A glass membrane electrode measures pH. Its thin glass bulb is selectively permeable to hydrogen ions, so a potential develops at the glass–solution interface that changes with hydrogen ion activity (pH). When you compare this sensing electrode to a stable reference electrode, the measured potential tracks pH, with a typical slope of about 59 mV per pH unit at room temperature. This makes it the standard tool for pH measurement because the glass responds specifically to H+ and provides a reliable, reproducible signal. Other options describe sensors that aren’t designed for monitoring hydrogen ion activity—one is a polymer-based sensor for other targets, another is a solid-state crystal sensor used in different contexts, and the gas-sensing electrode is for gases, not aqueous pH.

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