Concentrated saline, NaCl 20%
So far we have been talking about litres.
20% saline would never come in a litre.
Its usually available in little plastic containers, each containing 10ml. I cannot think of a situation which would call for a litre of 20% NaCl, and if you encounter such an instance in your practice, please email me, so I can marvel at it. Now, AstraZeneca originally made this 20% stuff as a vein sclerosant. Needless to say, it remains a peripheral venous sclerosant, even when it is given with the noble intent of decreasing intracranial pressure or increasing serum sodium. It should only be given through a central line.
Given that it is a 20% solution, one might expect there to be 20g of salt in every 100ml of water; thus, every 10ml plastic vial contains 2g of salt. This contributes 34.22 mmol of sodium and chloride, each.
Lavoisier have a pdf describing the properties of their product, to which I referred when reading about this.
In some surreal world where litre bags of 20% saline are available, each litre bag of 20% saline contains 200g (3.422 moles) of sodium chloride.