[higha (OP)]

Hello out there!

How can you determine and justify how high (approximately) the proportion (%) of HCl is that has to be neutralized (with sodium or potash lye) before precipitation?

I've been researching for over two hours and I still have no idea, that's why I am asking....

Best regards
- R

[Eternal Student]

Hi.
   I would have thought measuring the pH of the solution is a good place to start.   

Do you want to provide more information about what your experiment is and what else might be in solution with your HydroChloric acid?   What precipitate are you expecting anyway?
Obviously you can also ask more questions anytime. 

Best Wishes.

[Bored chemist]

Hello out there!

How can you determine and justify how high (approximately) the proportion (%) of HCl is that has to be neutralized (with sodium or potash lye) before precipitation?

I've been researching for over two hours and I still have no idea, that's why I am asking....

Best regards
- R

Essentially all of it.
I can make a solution of , for example, EuCl3 in water.
Only a haze of Eu(OH)3 would form.

[higha (OP)]

As the title suggets, my experiment is about the rare earth metals.
Other components must be removed for purification.
The respective waste is usually first dissvoled in acidic form with 10 M HCl.
Secondly, the rare earth metals are precipitated and detached in the form of their oxalates.
After the decomposition, the pH value must  be raised to pH 1 by adding soda or potash lye so that the precipitation works.
Now I have to give a justified estimate of how high the proportion of Hcl should be neutralized before the precipitation.

Thanks in advance!

[Bored chemist]

Now I have to give a justified estimate

Is this homework help?