Understanding pE and Redox Conditions
The pE value represents the redox potential of a system, similar to how pH represents acidity. It indicates whether a system is oxidizing (high pE) or reducing (low pE).
- High pE values (e.g., > 7) indicate strongly oxidizing conditions.
- Low pE values (e.g., < 0) indicate strongly reducing conditions.
- Intermediate values represent varying degrees of oxidizing or reducing potential.
Relating pE to Dissolved Oxygen (DO)
Dissolved oxygen (O₂) is a molecule that exists in its oxidized state. It is most stable and typically found in higher concentrations under oxidizing conditions.
Conversely, in highly reducing environments (low pE), oxygen can be consumed or reduced to other chemical species, leading to lower dissolved oxygen concentrations.
Comparing pE Values for Water Samples
The pE values provided for the four water samples are:
- pE = – 4.1 (Strongly reducing)
- pE = 1.0 (Slightly oxidizing/neutral)
- pE = 7.0 (Neutral/mildly oxidizing)
- pE = 13.9 (Strongly oxidizing)
Determining Highest Dissolved Oxygen Concentration
The highest concentration of dissolved oxygen (O₂) is expected in the sample with the most oxidizing conditions. Comparing the given pE values, pE = 13.9 is the highest value, indicating the strongest oxidizing environment.
Therefore, the concentration of dissolved oxygen shall be highest in the water sample with pE = 13.9.
Important Questions from Environmental Chemistry - Teaching
Which of the following chemicals is used to cause artificial rain (cloud seeding)?
Which of the following is a non-renewable source of energy?
- Consider the following statements about solubility of gases in surface water.
A. Equilibrium concentration of a dissolved gas in water as per Henry's law is referred to as its saturation value
B. There may be more dissolved gas in water than its saturation value in water
C. It is more common for a dissolved gas to be present in less amount in water than its saturation value in water
D. The excess or deficit of a dissolved gas compared to its saturation value cannot be brought back to saturation level in water
E. Solubility of gas depends on partial pressure of the gas but is independent of purity of water
Choose the correct answer from the options given below: - Which is not a preferable characteristics of water to be used as green solvent ?
- Which of the following reaction involves the principle of green chemistry ?
