CO2-Sensing probe (electrochemical device based on pas-permeable membrane)
Eind=A-0.0592*log[CO2(aq)]ext, where A is constant
which of the following may interfere with these measurements, if present in the aqueous solution: O2, N2, NO2 and Why?
To determine which of the following compounds may interfere with the CO2-sensing measurements, we need to consider their electrochemical behavior.
In the equation Eind=A-0.0592*log[CO2(aq)]ext, Eind represents the electrode potential, [CO2(aq)]ext is the concentration of CO2 in the external solution, and A is a constant. This equation suggests that the electrode potential varies logarithmically with the concentration of CO2.
Let's analyze the potential interference of each compound:
1. O2 (Oxygen): Oxygen is not expected to interfere significantly with the CO2-sensing probe. Electrochemically, it does not react with CO2 in the same way and therefore should not directly affect the electrode potential.
2. N2 (Nitrogen): Similar to oxygen, nitrogen is not expected to interfere with the CO2 measurements. Nitrogen is inert and does not undergo redox reactions or significant interaction with CO2.
3. NO2 (Nitrogen Dioxide): Nitrogen dioxide is an oxidizing agent and can potentially interfere with the CO2 measurements. NO2 can undergo redox reactions and react with certain electrode materials, causing a change in the electrode potential and leading to inaccurate CO2 measurements.
In summary, among the compounds mentioned, only NO2 (nitrogen dioxide) may interfere with the CO2-sensing measurements. O2 (oxygen) and N2 (nitrogen) are unlikely to cause significant interference.
It's important to note that this analysis is based on general knowledge of electrochemical behavior. The specific electrode material and device design should be considered in more detailed experimental settings to fully evaluate the potential interference of these compounds.