Thank you Pharmer, that makes sense! So the ice bath during NaOH is to help cool and slow the reaction?
When you add any salt (and NaOH is the Hydroxide Salt of Sodium) to water some heat is released as the salt breaks apart into ions. You'll find this in a general chemistry textbook under the "heat of dissolution" section. NaOH just so happens to have a huge
heat of dissolution value, so huge that it can actually raise the temperature of the water to 100*C! Obviously there are very few situations where a beaker of boiling pH 14+ solution would be desired, so the ice bath and gradual addition helps to keep the temp down.
This is also why my favorite poem from the Chem Lab exists:
"Always do what you oughtta,
Add the acid to the watah."
We add things to the water, not the other way around. If you want to try a fun & terrifying experiment (Please Don't!) put on your labcoat, gloves, goggles, and rubber apron and add a drop of water to a small pile of crystalline NaOH. The drop will boil instantly (it's like a tiny explosion) & fling NaOH crystals all over the lab!
When adding the NaOH directly to the juice and not to water first the idea is to keep the volume roughly the same. I was wondering why not add the HCl directly to the solvent during salting to keep the volume the same also. Then I realised the water the HCL is dissolved in becomes the solution that the target molecule migrates into. Is this thinking correct?
That is correct. If you added 8 drops of HCl into the solvent you would end up with solvent with a bunch of freebase Mescaline in it & 8 drops of water with a tiny bit of Mescaline HCl.
What some people do when salting mescaline is to put 1-3 hundred mL of water in with the solvent, add a drop of HCl, mix it around & allow the phases to settle, then check the pH of the water. Repeat drop by drop until the pH is around 5.5 then separate the layers and evaporate the water to recover mescaline HCl.
This is pretty fun, Yoshi! Keep the questions coming; it might be neat to have a thread full of just general chemistry Q&A...