adding lye and pH going down?

[seeohhdee]

i am doing an A/B with lye and during the basifying step, I am attempting to prepare fome basified water, but the more lye i add, the pH is going down slightly. WTF?

i started with 200mL and approx 50g of lye

does this sound right? what could be wrong?

thanks...

 

[double]

May I ask you how are you checking your pH? By a paper strip, a digital meter or something else?
I also can't figure out a reaction in which NaOH becomes acid... NaOH + HCl -> NaCl + H2O, 2NaOH + H2SO4 -> Na2SO4 + 2H2O

Which acid and solvent did you use?

Thank you

 

[benzyme]

sounds like a probe out of cal.

 

[۩]

sounds like a probe out of cal.

This. Recalibrate.

Also, pH goes down after every pull. So you may have to add some after each pull.

Another thing, high basic solutions can seriously warp pH meter diodes. This is why I do not use pH meters for extractions. They will read significantly off after taking a pH 13-14 measurement and need to be recalibrated.

 

[seeohhdee]

im using a brand new digital meter. i calibrated before the extract. it wasnt getting acidic it just got up to 11.9 and as i added more lye it went down to about 11.4

i used a molarity converter and just basified normally and the problem fixed itself; the digital meter started working fine after that.

weird.

but thanks for the suggestions, everyone. there was probably just some schmutz on my probe.