Lack of considering new approaches leads to stagnation. In three - four years, I think that most teks will be adjusted to add IMPROVED quantitative amounts of material and reagents. For example: the claim that adding more NaOH is going to help break an emulsion. Actually... maybe not. As more NaOH is added to the solution, viscosity increases and will make it MORE difficult for separation.

Also, the amount of NaOH suggested, in the popular teks, is absurd! Even in 1 liter of water, way overkill and wasteful. I understand why people have written them as such - most won't take the time to bother monitoring pH though out the process. I think the authors assume most people will read [half of] the tek and just start dumping chems in. And... that's happened. Lol.

But, pH and pOH have a logarithmic relationship with concentration (molarity). One mol of NaOH is roughly 40 grams. Ok, cool - molarity is determined by dividing the amount of NaOH (mols) by the volume of the solution (liters). So, let's say you use a mol of NaOH (~40 grams) and one liter of total solution: 1 mol / 1 Liter = 1 mol/L (this is a solution that has a concentration of 1 M (Molarity).

pH or pOH can be related as: pOH = -log(OH); pH = -log(H); and pOH = -log(1 M NaOH) = 0... but, pH and pOH are complimentary. The pH = (14 - pOH) = (14 - 0) = 14.

The concentration needed to achieve a specific pOH or pH can be as followed:
[H] = 10^-(pH) ; and [OH] = 10^-(pOH)....

So, let's assume you want a pH of 13. (A.k.a. pOH of 1)

[H]= 10^-(13) = 1.0x10^−13 M ; [OH] = 10^-(1) = 0.1 M.

Ok, so we need 0.1 M solution of NaOH. So M = (mol/L) ; then (M)(L) = mol.

We know that the volume is 1 L. We know the molarity is 0.1 M, so (0.1 M)(1 L) = 0.1 mols.

NaOH has a M.W. of ~40 grams/mol. So, 40 (g/mol) * 0.1 (mol) =....... wait for it..... wait for it.... 4 grams.

People have been adding 50 grams!!!!!! That's 10x more than theoretically needed. I decided to test the theory - you can see the results here. (Also, I never updated the final results - I performed a second pull - smashing the old yield percent of ~1.4 %..... we're well over 2 %, now.... 2 pulls, ~ 10 grams of NaOH)

Why are the teks designed with such inefficiency and wastefulness?" If you even used 10 grams of NaOH, you'd be fine. So, my theory is that most people DO read and repeat (or try, lol). Only a few ask why.

Take care,
ACY

P.S. - if any of the above seems like alien language, just ask. I'll try to simplify it if I can, but I think it would be most rewarding to dig into the topic and learn what the explanation means, rather than the simple answer.