Hi , I have this question and I do not know what steps to follow. Please help guide me. It will be really appreciated.
Calculate the extent of oxidation in a stream where water it's in equilibrium with atmospheric oxygen and had a pH pic 6.5 (a(H3O+) =antilog (-6.5) ). The effluent from the tannery contains 26 mg/L of Cr3+
Thank you for helping :)
To calculate the extent of oxidation in a stream, we need to determine the oxidation state of chromium (Cr) in the effluent from the tannery and compare it with the oxidation state of chromium in water at equilibrium.
Here are the steps you can follow:
Step 1: Determine the oxidation state of chromium in the effluent:
- Given that the concentration of Cr3+ in the effluent is 26 mg/L, we assume that all the chromium is in the +3 oxidation state.
Step 2: Calculate the oxidation state of chromium in water at equilibrium:
- Water in equilibrium with atmospheric oxygen usually contains chromium in the +6 oxidation state. This is because atmospheric oxygen is a strong oxidizing agent and can convert Cr3+ to Cr6+.
Step 3: Calculate the extent of oxidation:
- To calculate the extent of oxidation, we need to compare the oxidation state of chromium in the effluent (Cr3+) with the oxidation state of chromium in the water at equilibrium (Cr6+).
- Since Cr6+ is two units higher in oxidation state than Cr3+, the extent of oxidation can be calculated as follows:
Extent of oxidation = (Number of moles of Cr6+)/(Number of moles of Cr3+)
Step 4: Convert concentration to moles:
- To calculate the extent of oxidation, we need to convert the concentration of Cr3+ in the effluent to moles.
- Use the molar mass of Cr3+ to convert the concentration from mg/L to moles/L.
Step 5: Calculate the extent of oxidation:
- Divide the number of moles of Cr6+ (calculated in step 2) by the number of moles of Cr3+ (calculated in step 4) to get the extent of oxidation.
By following these steps, you should be able to calculate the extent of oxidation in the given stream.