In article ,
Grumach Macabre of Auchterloonie wrote:

Yes, lots. And they will not keep. Salt is used to remove water,

And much of it remains behind. Not a lot attaches to the onions.

I agree that onions absorb vastly less salt than most pickles do,
but they are still pretty salty. I don't like large (i.e. normal
for Blighty) quantities of salt, and have to drink massive amounts
of water to cope with it, so I notice.

to create acidity (don't ask me how), and to be in itself hostile
to bacteria, fungi etc.

The chloride ions and the hydrogen ions in the pickle from
(respectively) the salt and the acetic acid act as if they were
hydrochloric acid.

Grrk. Firstly, it also works even if there is no other acid present.
Secondly, sodium binds far more strongly to chloride than hydrogen
does. There is something rather more subtle that goes on.

Yes, I did O-level chemistry, too - and my answer comes from that.
The answer is university-level.


Regards,
Nick Maclaren.