How Does a pH Meter Work and What Role Does the Reference Electrode Play?

  • Thread starter Thread starter Mizuki168
  • Start date Start date
  • Tags Tags
    Ph Work
AI Thread Summary
A pH meter operates using two electrodes: a pH electrode, typically a glass electrode, and a reference electrode, often made of Ag/AgCl. The pH electrode measures the concentration of hydrogen ions in a solution, generating an electric potential that is converted into pH units. The reference electrode provides a stable electric potential, essential for accurate measurements, by maintaining a constant concentration of chloride ions in its solution. It must be submerged in the test solution to close the circuit and allow for relative potential measurement. Understanding the role of the reference electrode is crucial for accurate pH readings.
Mizuki168
Messages
5
Reaction score
0
Hey guys, so I have a project on the pH meter. Basically on what it is, what it's used for, how it works, and what principles does it run on. It is a group project but we can't seem to figure out some points and we've become very confused!

Mainly, it's how it works. We researched and understood that the pH meter has electrodes and it kind of works like a thermacouple thermometer. There are 2 electrodes (a pH electrode and a reference electrode). The pH electrode, according to us, is a glass electrode that has a membrane made out of some metal. When the glass electrode is put in the tested solution to determine the pH level, the hydrogen ions go in the glass electrode and then in turn some metal ions from the membrane go into the solution? And then there is a electric potential difference that is sent to the voltmeter that helps convert it into pH units.

But out real problem is, is what use is the reference electrode. We've done a lot of research on it and everywhere just says that it's to provide a stable electric potential. But how? And why?
 
Physics news on Phys.org
www.ph-meter.info[/url] and specifically [url=http://www.ph-meter.info/pH-electrode-construction]www.ph-meter.info/pH-electrode-construction[/URL] contain most of the information you need.

Reference electrode is usually Ag/AgCl electrode, not different from those routinely used as a reference in many electrochemical experiments.
 
Last edited by a moderator:
Borek said:
www.ph-meter.info[/url] and specifically [url=http://www.ph-meter.info/pH-electrode-construction]www.ph-meter.info/pH-electrode-construction[/URL] contain most of the information you need.

Reference electrode is usually Ag/AgCl electrode, not different from those routinely used as a reference in many electrochemical experiments.[/QUOTE]


Thank you for the websites however even after reading them I'm not quite understanding anything about the reference electrode...
 
Last edited by a moderator:
I am not sure what the problem is. Such an electrode is made of Ag wire covered with AgCl, submerged in solution of chlorides of known concentration (usually either 1M or saturated KCl). Its potential is constant because that's the way electrodes work - this particular electrode has potential depending on the concentration of chlorides, as long as this concentration is constant, potential is constant as well.

--
 
Oke...so the chloride stays in the reference electrode. Then why must it be dipped in the solution being tested for pH level?
 
Not sure what your question is. Why whole electrode must be dipped? You can't measure concentration remotely. Why reference electrode must be dipped? You have to close circuit, you are measuring relative potential.

--
 
I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
Back
Top