The Sodium can be separated from the mixture by strong acid cation resin

the sodium chloride concentration is more 80 g/L, so, the resin for the exchange of sodium is not feasible for me.

What is the purpose of this? Do you simply wish to remove the HCl?

Separation is not easy but if you wish to just remove the HCl (and know its concentration) potentially you could react the mixture with sodium hypochlorite, which could leave your mixture containing only NaCl

NaClO + 2 HCl → H2O + NaCl + Cl2

Obviously without the proper facilities (i.e. Fume Cupboard) and training this would be dangerous and it evolves chlorine gas!!!

Disclaimer:

I take no responsibility in any way with respect to how you use this information and any experimentation you do perform is at your own risk.

Also, if you want the HCl left - I am not sure if it would work as it is not something I have attempted but in theory using Le Chatelier's principle you could shift the equilibrium in your favour by adding ethanol to the mixture.

In sufficient concentration this would force the NaCl to crystallize out of solution (due to hydrogen bonding between ethanol and water). Since HCl is more soluble it should remain. You then only need to remove the ethanol which should be able to be evaporated off :-)

Thank you for all the comments

Thanks Thomas - I knew I must be tired, why would I not consider NaOH lol :-)

I agree that the question needs more elaboration, I was not sure if Boopathy wants the HCl or the NaCl - which are both relatively cheap and available chemicals... begging the question as to why you want or need to do this?

I had not considered that this might be some large commercial-scale situation. It make sense that the likely wants to conserve the acid in that case. Presumably if he used the solvent addition then (ethanol or acetone etc...) and reclaimed the solvent he would end up with little acid or solvent loss + lots of salt :-)

The simple way is by distillation. HCl and water form a constant boiling solution at 25% HCl and this can be collected as a condensate, with the residual solution being aqueous NaCl.

In my case HCl should be recovered for reuse. I used to distill the HCl by condensation. But , not all the HCl is condensed, i think it formed a azeotrophic mixture. I tried isopropylalcohol, but, this further diluted the solution. The solvent addition helps to reduce the salt in the aqueous solution.

I see, yes complete elimination by distillation would be hard.

I think you should attempt the use of a more volatile solvent such as ethanol or for my interest also, acetone as Thomas suggested :-)

Please feedback of what happens.