How to determine the molarity of a 1.8% NaCl solution.

Answer 1

You need the density.
1.8% NaCl (by mass or w/w) means 1.8 g NaCl/100 g solution.
1.8g NaCl/molar mass NaCl = moles NaCl.

Then 100 g solution converted to mL from the density. volume = 100 g/density and convert mL to L.

M = moles/L.