Hi,
I did an extraction experiment. I've got my basic layer, and getting my acidic salt in return. To do this, I am instructed to first "add a small amount of NaCl to help with the product precipitation". Then, again I am instructed to add HCl to "acidify" the solution. With these instructions, I will get my precipitate.
The question is, what would happen if I added too much HCl and, more importantly, can you tell me why it would not help with the precipitation by adding too much or extra of HCl to the basic layer?
I actually did this by accident in the lab. I miscalculated using the formula c1v1=c2v2 and added 9mL of the HCl which should be only .075mL. I'm trying to remember what happened to my solution, but obviously there was too much HCl in it.
Please help,
Thanks!
I wish I could help but there is nothing in your post to tell us what experiment you were doing. Sorry. My tea leaves aren't working tonight.
What type of info must I supply? Or is it too much info to be asked?
If I can reclarify..
In the experiment, I am separating an unknown organic mixture of two solids by extraction. From this I will get the Basic layer, and acidic layer, both will be the source for isolating the precipitates from each.
In the context of the experiment, I've added some HCl to the basic layer and the solid precipitates. If I continue to add acid, the solid will redissolve. Why does this happen?
I hope that helps.
Also, the solvent used for extraction is ethyl acetate. So, the organic mixture to be separated by extraction dissolved in ethyl acetate.
Frankly, I don't know why it redissolves upon adding too much HCl but why not recalculate the c1v1 = c2v2 and see how much NaOH to add to neutralize that extra HCl you added. That should get you back to the starting point or at least where you had the ppt form.
Thank you.
Hi there,
Adding too much HCl to your solution can potentially have several consequences and may not help with the precipitation of your desired product. Here's why:
1. Excessive Acidic Environment: HCl is a strong acid and adding too much of it will result in an excessively acidic environment. This can have an undesirable effect on the solubility of your desired precipitate. Some products prefer a specific pH range for precipitation, and an excess of HCl will shift the pH far beyond that range, hindering the formation of the precipitate.
2. Ionization Effects: The excess of HCl will increase the concentration of hydrogen ions (H+) in the solution. This increase in ionic concentration can potentially cause other ions to stay in solution rather than precipitate. The excess H+ ions may compete with the desired product ions for the same anions, preventing the formation of the precipitate.
3. Reverse Solubility: In certain cases, the addition of excessive acid can cause the reverse solubility effect. Some compounds may have limited solubility in an acidic environment, but further acidification can make them more soluble again. This means that adding more HCl can actually make your desired product remain in the solution rather than precipitate.
4. Safety Concerns: Adding too much HCl can also pose safety risks. The excessive release of acid fumes can be hazardous and potentially harm your health or damage equipment.
Regarding your accidental addition of 9 mL of HCl instead of the intended 0.075 mL, it is difficult to predict the exact outcome without more information about the specific experiment and compounds involved. However, it is likely that the excessive amount of HCl created an overly acidic solution, which may have prevented or altered the precipitation process.
In situations like this, it is always important to consult with your lab instructor or supervisor to address any safety concerns and determine the best course of action based on the specific experiment you were conducting.
I hope this helps clarify what might have happened and why adding too much HCl would not help with the precipitation. If you have any further questions, feel free to ask!